Nevus Sebaceus

Background

This is a congenital abnormality characterized by a fleshy, raised, yellow papillomatous nodule, usually appearing on the head and neck. Aside from cosmetic issues, there is a definitely increased risk of malignancies, particularly basal cell carcinomas, arising within these lesions. A complete excision is usually curative.

OUTLINE

Epidemiology

Disease Associations

Pathogenesis

Laboratory/Radiologic/Other Diagnostic Testing

Gross Appearance and Clinical Variants

Prognosis and Treatment

Commonly Used Terms

Internet Links

EPIDEMIOLOGY CHARACTERIZATION

SYNONYMS Nevus Sebaceus of Jadassohn

DISEASE ASSOCIATIONS CHARACTERIZATION

APLASIA CUTIS CONGENITA

Didymosis aplasticosebacea: coexistence of aplasia cutis congenita and nevus sebaceus may be explained as a twin spot phenomenon.

Happle R, Konig A.

Department of Dermatology, University Hospital Marburg, Germany.
Dermatology 2001;202(3):246-8 Abstract quote
BACKGROUND: Co-occurrence of aplasia cutis congenita and nevus sebaceus has sometimes been observed.

OBJECTIVE: We propose a genetic mechanism that may explain this coexistence of two different congenital skin disorders.

Methods and RESULTS: We review 15 cases as reported in the literature and present an additional case. To explain the temporal and spatial proximity of the two skin lesions we advance the concept of twin spotting for which we propose the term didymosis (Greek didymos = twin). In an embryo heterozygous for two different recessive mutations localized on either of a pair of homologous chromosomes, an event of somatic recombination would occur at an early developmental stage, giving rise to two different cell clones homozygous for either mutation.

CONCLUSION: The concept of didymosis aplasticosebacea is so far hypothetical. Future molecular research may show whether this concept holds true.

APOCRINE CARCINOMA

Tubular apocrine carcinoma arising in a nevus sebaceus of Jadassohn.

Jacyk WK, Requena L, Sanchez Yus E, Judd MJ.

Department of Dermatology, University of Pretoria, Republic of South Africa.
Am J Dermatopathol 1998 Aug;20(4):389-92 Abstract quote
We present an example of tubular carcinoma that developed within a nevus sebaceus of Jadassohn on the scalp of a 53-year-old woman. The neoplasm showed features of sebaceous and apocrine differentiation.

We review the literature about the malignant neoplasms arising in the nevus sebaceus of Jadassohn.

DESMOPLASTIC NEUROEPITHELIAL TUMOR

Desmoplastic neuroepithelial tumor of infancy in the nevus sebaceus syndrome: report of a unique constellation and review of the literature.

Kopniczky Z, Kobor J, Maraz A, Vajtai I.

Department of Neurosurgery, University of Szeged Health Sciences Center, Hungary.

Pathol Res Pract 2001;197(4):279-84 Abstract quote
The nevus sebaceus syndrome (NSS) is a neurocutaneous disorder characterized by unilateral hyperplasia of skin appendages and skeletal hemihypertrophy, hemimegalencephaly, or hemiatrophy along with disabling seizures. Despite the proneness of the dermal stigmata to eventually undergo neoplastic transformation, the malformative lesions of the central nervous system rarely evolve into frank tumors.

We present the case of a 10-year-old girl with left-sided sebaceus nevi, ipsilateral enlargement of the skull, and a desmoplastic neuroepithelial tumor (DNET) in the right fronto-parietal area of the brain. The tumor was removed by surgery. Histologically, it corresponded to a mitotically active small-cell anaplastic astrocytoma with genuine desmoplasia. Investigative methods included immunohistochemical positivity for glial fibrillary acidic protein, lack of expression of neuronal markers, and ultrastructural documentation of sheaths of basal lamina and collagen around tumor cells.

A survey of the literature of brain tumors associated with NSS revealed two cases of histologically verified pilocytic astrocytomas, and one each of a choroid plexus papilloma, a mixed glioma, and a meningioma, as well as a subependymal giant cell astrocytoma--the latter possibly in an overlap syndrome of NSS and tuberous sclerosis.

We hypothesize that the tumor described herein, one involving both atypical differentiation and enhanced growth potential, is paradigmatic of neuropathological events to be expected in the NSS.

ECCRINE SPIRADENOMA

Spiradenoma arising in a nevus sebaceus of Jadassohn: case report and literature review.

Shapiro M, Johnson B Jr, Witmer W, Elenitsas R.

University of Pennsylvania Medical Center, Department of Dermatology, Philadelphia 19104, USA.
Am J Dermatopathol 1999 Oct;21(5):462-7 Abstract quote
Nevus sebaceus (NS) of Jadassohn is usually a verrucous plaque on the scalp or face that arises secondary to disordered development of epithelial, pilar, sebaceous, and apocrine structures. The emergence of neoplasia is a late stage in the natural history of NS. Although most neoplastic proliferations are benign, several malignant tumors have arisen in this lesion.

We describe the first case of a benign spiradenoma arising in an NS on the scalp in a 72-year-old Caucasian woman. Reexcision was recommended to prevent the development of a second neoplastic process and to avoid the rare occurrence of a malignant transformation of the existing neoplasia. The patient declined reexcision and remains under observation. The spectrum of tumors arising in NS are described and are categorized according to behavior. Syringocystadenoma papilliferum is the most commonly observed benign growth, whereas basal cell carcinoma is the most frequently seen malignant process.

The signs of tumor development (benign or malignant) within an NS are reviewed, and treatment recommendations are provided. The clinical course of rare and unique aggressive neoplasms originating in NS is summarized.

NEUROFIBROMATOSIS

Segmental neurofibromatosis in association with nevus sebaceus of Jadassohn.

Lupton JR, Elgart ML, Sulica VI.

The George Washington University Hospital, Washington, DC 20037, USA.
J Am Acad Dermatol 2000 Nov;43(5 Pt 2):895-7 Abstract quote
We describe an unusual case involving the simultaneous occurrence of segmental neurofibromatosis (Type V NF) in a patient with a large nevus sebaceus of Jadassohn in the same physical distribution.

Causative mechanisms of development of these 2 genetic disorders have not been definitively linked. Factors producing these diseases probably involve similar tissues at the same point in development because both have been reported in association with central nervous system anomalies and have been classified among the neurocutaneous syndromes.

This is a case of a nevus sebaceus occurring in association with and in the same physical distribution as segmental NF. These disorders most likely represent a spectrum of disease within the phakomatoses.

OCULAR CHANGES

A new neurocutaneous syndrome: nevus sebaceus syndrome.

Kucukoduk S, Ozsan H, Turanli AY, Dinc H, Selcuk M.

Department of Pediatrics, Ondokuz Mayis University, Samsun, Turkey.
Cutis 1993 Jun;51(6):437-41 Abstract quote
We describe a case of nevus sebaceus syndrome characterized by a linear sebaceous nevus, extending on the left half of the face from forehead to lower neck, including the auricle; alopecia on the temporoparietal region; generalized hypotonia; insufficiency of eyes in following moving objects and insufficiency in controlling the head; lipodermoid cysts in the left and right eyes; bilateral conjunctival masses; corneal vascularization in the right eye; coloboma of the left eyelid and right optic disc. T

his is a rare case of a sebaceous nevus occurring concomitantly with optical and central nervous system abnormalities.

SEBACEOUS CARCINOMA

Sebaceous carcinoma, trichoblastoma, and sebaceoma with features of trichoblastoma in nevus sebaceus.

Misago N, Kodera H, Narisawa Y.

Division of Dermatology, Department of Internal Medicine, Saga Medical School, Saga, Japan.
Am J Dermatopathol 2001 Oct;23(5):456-62 Abstract quote
A 73-year-old woman had a linear yellowish plaque on the upper part of her right ear since birth.

She presented because of the sudden growth of a nodule within the plaque. The plaque was waxy and yellowish, arching around the upper part of the ear. A reddish to yellowish large nodule was seen within the central part of the arc-shaped plaque; in addition, a small pigmented nodule, a small skin-colored nodule, and a few pigmented papules were observed in the anterior half of the arched plaque.

Histopathologic examination revealed the large nodule to be sebaceous carcinoma, the small pigmented nodule to be trichoblastoma, the small skin-colored nodule to be sebaceoma with the features of trichoblastoma, a few pigmented papules to be superficial trichoblastomas due to primitive follicular induction, and the linear yellowish plaque to be nevus sebaceus. Although our literature search revealed scanty reports of definite cases of sebaceous carcinoma in nevus sebaceus, the presented case demonstrated the occurrence of sebaceous carcinoma in nevus sebaceus.

Malignant neoplasms occurring in nevus sebaceous seem to be extremely rare, but care should be taken when a large nodule suddenly grows in a lesion of nevus sebaceus, especially in older adults. The presented case also suggested a close relation between trichoblastoma and sebaceoma. The cytokeratin staining pattern could not distinguish between sebaceous and follicular neoplasms in our case.

SPECKLED LENTIGINOUS NEVUS

Phacomatosis pigmentokeratotica: speckled-lentiginous nevus in association with nevus sebaceus.

Langenbach N, Hohenleutner U, Landthaler M.

Department of Dermatology, University of Regensburg, Germany.
Dermatology 1998;197(4):377-80 Abstract quote
We report a case of a congenital nevus sebaceus with numerous brown macules and papules in the left auricular region.

In the same lesion, pigmented basal cell carcinomas developed later in life. Additionally, on the left side of the neck, both shoulders and the left arm, features of nevus spilus with melanocytic and blue nevi were present.

Such a combination of nevus sebaceus with melanocytic lesions may be explained by the concept of twin spotting and represent another case of phacomatosis pigmentokeratotica.

TRICHOBLASTOMA

Trichoblastoma is the most common neoplasm developed in nevus sebaceus of Jadassohn: a clinicopathologic study of a series of 155 cases.

Jaqueti G, Requena L, Sanchez Yus E.

Department of Dermatology of Fundacion Jimenez Diaz, Universidad Autonoma, Madrid, Spain.
Am J Dermatopathol 2000 Apr;22(2):108-18 Abstract quote
Nevus sebaceus of Jadassohn is a hamartoma that combines epidermal, follicular, sebaceous, and apocrine gland abnormalities. Classically, several types of cutaneous neoplasms have been associated with this hamartoma, with basal cell carcinoma being the most frequently described malignancy.

We studied a series of 155 examples of nevus sebaceus of Jadassohn with clinicopathologic correlation. Several histopathologic changes related to the age of the patients were found. In our series, we could not identify any cases of authentic basal cell carcinoma. In contrast, several examples of primitive follicular induction and of trichoblastomas were seen. Other cutaneous hamartomas, hyperplasias, and neoplasms found in our series of nevus sebaceus of Jadassohn included syringocystadenoma papilliferum, sebomatricoma, apocrine gland cyst, poroma, different histopathologic variants of warts (classic warts, tricholemmoma, and desmoplastic tricholemmoma), primitive follicular induction, and ductal induction. In our series, no examples of malignant neoplasms were identified.

On the basis of these findings, the classically recommended treatment for this hamartoma, which consists of early excision to prevent the development of malignancy, seems to be inappropriate.

Clear cell trichoblastoma in association with a nevus sebaceus.

Tronnier M.

Department of Dermatology, Medical University of Lubeck, Lubeck, Germany.
Am J Dermatopathol 2001 Apr;23(2):143-5 Abstract quote
Nevus sebaceus is a hamartoma that is frequently associated with various neoplasms. Among the neoplasms observed in sebaceus nevi, trichoblastomas are the most common.

The present case, to my knowledge, is the first description of a clear cell variant of trichoblastoma.

PATHOGENESIS CHARACTERIZATION

ANDROGEN RECEPTORS

The role of androgen receptors in the clinical course of nevus sebaceus of Jadassohn.

Hamilton KS, Johnson S, Smoller BR.

Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Mod Pathol 2001 Jun;14(6):539-42 Abstract quote
Nevus sebaceus of Jadassohn (NSJ) is a benign, congenital hamartoma that often presents at birth, appears to regress in childhood, and grows during puberty, suggesting possible hormonal control.

We studied 18 cases of NSJ from children and adults for immunohistochemical evidence of androgen receptor expression. The lesions were evaluated for location and pattern of immunostaining, and these findings were compared between age groups, sexes, and to androgen receptor expression in normal skin. Androgen receptor positivity was seen in the sebaceous glands, in eccrine glands with and without apocrine change, and rarely in keratinocytes in the sebaceous nevi. There were no significant differences in staining location or pattern between the age groups or sexes.

Normal skin showed similar staining in the sebaceous glands but did not show staining of the eccrine glands or keratinocytes. Androgen receptors are present in all epithelial components of NSJ, but there is no change in androgen receptor expression during puberty.

LABORATORY/RADIOLOGIC/
OTHER TESTS
CHARACTERIZATION

RADIOLOGIC

Proton magnetic resonance spectroscopy of linear nevus sebaceus syndrome.

Kruse B, Pouwels PJ, Christen HJ, Frahm J, Hanefeld FA.

Abteilung Kinderheilkunde; Schwerpunkt Neuropadiatrie; Georg-August-Universitat, Gottingen, Germany.

Pediatr Neurol 1998 Feb;18(2):176-80 Abstract quote
Cerebral metabolites of a patient with linear nevus sebaceus syndrome and hemimegalencephaly were determined at 18 and 30 months of age by localized proton magnetic resonance spectroscopy.

Clinically, the patient suffered from hemiparesis and epileptic seizures. At 18 months of age, spectroscopy of the enlarged hemisphere revealed decreased N-acetylaspartate mainly in parietal white matter relative to the unaffected hemisphere. One year later, white matter studies indicated both reduced N-acetylaspartate and elevated myoinositol. In insular gray matter the previously normal concentrations of creatine, choline-containing compounds, myoinositol, and glutamine were increased. The findings are consistent with mild neuroaxonal loss or damage (white matter) and glial proliferation (cortical gray and white matter) of the affected hemisphere.

The metabolic disturbances indicate disease progression but are less pronounced than in older patients with hemimegalencephaly.

Cortical reorganization in linear nevus sebaceous syndrome: a multimodality neuroimaging study.

Levy-Reis I, Casasanto DJ, Gonzalez JB, Alsop DC, Glosser G, Maldjan JA, French J, Detre JA.

Department of Neurology, University of Pennsylvania, USA.
J Neuroimaging 2000 Oct;10(4):225-8 Abstract quote
The authors report the findings of multimodal structural, functional, and metabolic imaging in a patient with linear nevus sebaceous syndrome, intractable seizures, and right megalencephaly.

Despite nearly continuous paroxysmal electrical activity from the megalencephalic region, imaging studies suggested nonfunctional tissue in this region with reorganization of cortical function to the unaffected ipsilateral hemisphere.

Hemispherectomy has been successfully performed in previous patients; however, it could have led to marked left hemiparesis with significant functional morbidity in this patient because of ipsilateral reorganization of the primary motor cortex.

GROSS APPEARANCE/
CLINICAL VARIANTS CHARACTERIZATION

GENERAL

VARIANTS

CEREBRIFORM

Cerebriform sebaceous nevus.

Ramesh A, Murugusundaram S, Vittel K, Kumar S, Janaki VR, Boopalraj JM.

Department of Dermatology, Madras Medical College, India.
Int J Dermatol 1998 Mar;37(3):220 Abstract quote
A 20-year-old man presented with a well-defined, soft to firm, freely mobile pinkish-yellow plaque of 9.5 cm over the right parieto-occipital region with a typical cerebriform appearance.

In total, nine folds were present with short black terminal hair in the sulci area. There was no follicular plugging. Skeletal survey and neurologic and ophthalmologic assessments were normal.

Skin biopsy was compatible with sebaceous nevus showing mature sebaceous glands in the upper dermis and mature apocrine glands in the lower dermis with malformed hair germ.

FAMILIAL

Familial occurrence of nevus sebaceus of Jadassohn: another case of paradominant inheritance?
Laino L, Steensel MA, Innocenzi D, Camplone G.

Department of Dermatology, Policlinico Umberto I, University "La Sapienza", Rome, Italy.
Eur J Dermatol 2001 Mar-Apr;11(2):97-8 Abstract quote
We describe two sibs (a boy and a girl) suffering from linear nevus sebaceus of Jadassohn. The parents are not affected.

This rare pattern of familial occurrence prompts us to suggest that these sibs represent a case of paradominant inheritance of a mosaic disorder.

PROGNOSIS AND TREATMENT CHARACTERIZATION

PROGNOSTIC FACTORS

MALIGNANCIES

Nevus sebaceus of Jadassohn: the head and neck manifestations.

Hagan WE.
Laryngoscope 1987 Aug;97(8 Pt 1):909-14 Abstract quote
The nevus sebaceus of Jadassohn (SNJ) is a congenitally-occurring, hamartomatous disorder of the skin and its adnexa of infrequent occurrence.

This presentation of five cases emphasizes the smooth, waxy, yellow-brown lesion's progression into a thickened sebaceous tumor of premalignant predilection. The incidence of neoplastic degeneration of these hamartomatous nevi may be as high as 30% with the capacity of metastasis occasionally reported. Because of malignancy risks as well as cosmetic considerations, early surgical removal is recommended. Previously unreported problems of dysphagia and malnutrition secondary to pulsion diverticulum at the esophageal inlet and cleft palate, obliterative aural stenosis with associated conductive hearing loss are documented.

Regardless of SNJ's occurrence as either an isolated lesion or as the fully developed syndrome, including mental retardation and epilepsy, this congenital malformation of the skin, its hair, and sebaceous glands presents rare and histologically intriguing problems for the practitioner.

Tumors arising in nevus sebaceus: A study of 596 cases.
Cribier B, Scrivener Y, Grosshans E.

Laboratoire d'Histopathologie Cutanee, Clinique Dermatologique des Hopitaux Universitaires de Strasbourg, France.

J Am Acad Dermatol 2000 Feb;42(2 Pt 1):263-8 Abstract quote
BACKGROUND: Prophylactic surgical excision of nevus sebaceus (NS) during childhood is often recommended because various neoplasms can occur on NS. The proportion of malignant tumors occurring on NS is highly variable among the published series, and there are controversies on the nature of these neoplasms because many of the previously described basal cell carcinomas could actually be trichoblastomas, which are benign follicular tumors.

OBJECTIVE: We retrospectively analyzed all cases of NS of our collection, excised during the period from 1932 through 1998, and recorded all associated epithelial and nonepithelial changes. We especially differentiated basal cell carcinomas from trichoblastomas by silhouette analysis and examination of the stroma. These findings were analyzed according to gender, age, and localization.

METHODS: Microscopic analysis of NS by two examiners was performed independently of clinical data.

RESULTS: A total of 596 cases were included from 290 females and 306 males, mean age 25.4 years (range, 1 month to 87 years); 232 were excised in children younger than 16 years. NSs were located on the scalp in 49.8% of cases. Basal cell carcinomas were found in 5 cases (0.8%, mean age 39.3 years) and benign tumors in 81 cases (13.6%, mean age 46.3 years). Syringocystadenoma papilliferum (n = 30, 15 males, 15 females) and trichoblastoma (n = 28, 7 males, 21 females) were the most frequent benign tumors. NS with associated tumors were located on the scalp in 79% of cases. Only 4 benign tumors (1.7%) and 2 warts were observed in patients younger than 16 years. Various types of epithelial hyperplasia were noted that could not be considered neoplasms, as well as epidermal and apocrine cysts.

CONCLUSION: The rate of malignant tumors arising on NS was very low and we did not observe such cases in children, who had associated benign tumors in only 1.7% of cases. Benign neoplasms were common and most of them occurred on the scalp; this was not a bias resulting from a longer duration before surgery. Trichoblastoma and not basal cell carcinoma was the most frequent follicular tumor associated with NS and showed a striking female predominance. Most trichoblastomas had previously been misdiagnosed but could actually be easily recognized by typical histologic features. Because most tumors occurred in adults older than 40 years, our study suggests that prophylactic surgery in young children is of uncertain benefit. Clinical follow-up is probably sufficient, and even those cases with clinical changes often proved to be benign tumors or warts.

Basal cell carcinoma originating from a nevus sebaceus on the scalp of a 7-year-old boy.

Turner CD, Shea CR, Rosoff PM.

Division of Pediatric Hematology-Oncology, Duke University Medical Center, Durham, North Carolina, USA.
J Pediatr Hematol Oncol 2001 May;23(4):247-9 Abstract quote
Basal cell carcinoma (BCC) occurs rarely in children and is most often associated with an underlying condition that predisposes patients to the development of malignancy. There have been numerous reports of BCC developing after puberty in nevus sebaceus; however, such occurrences have rarely been described in children.

We report a 7-year-old boy with BCC forming in a nevus sebaceus.

Malignant transformation in congenital sebaceous naevi in childhood.

Dunkin CS, Abouzeid M, Sarangapani K.

Department of Plastic and Reconstructive Surgery, Middlesbrough General Hospital, UK.

J R Coll Surg Edinb 2001 Oct;46(5):303-6 Abstract quote
Sebaceous naevi are uncommon congenital skin lesions with a well-recognised potential for neoplastic change.

They should be considered premalignant lesions as malignant degeneration, most commonly basal cell carcinoma and squamous cell carcinoma, occurs with a lifetime risk of between 5% and 22%. This incidence is equal to that of actinic keratosis and exceeds that of oral leukoplakia. Such change, however, is rare before puberty. Basal cell carcinoma may develop in children with naevoid basal cell carcinoma syndrome, xeroderma pigmentosum and rarely de novo but sebaceous naevus is the only solitary lesion in childhood associated with the development of basal cell carcinoma.

We present two cases of malignant transformation in a congenital sebaceous naevus occurring in childhood and review the literature and discuss the evidence upon which to base management guidelines.

TREATMENT

LASER

Linear nevus sebaceus of Jadassohn treated with the carbon dioxide laser.
Ashinoff R.

Ronald O. Perelman Department of Dermatology, New York University Medical Center, New York.
Pediatr Dermatol 1993 Jun;10(2):189-91 Abstract quote
A 10-year-old boy from Guiana was born with a linear nevus sebaceus covering his entire nose from the glabella area to the tip. Cosmetic appearance, which was the major concern of the patient and his family, was greatly improved by the use of the carbon dioxide (CO2) laser.

The CO2 laser has not been reported previously as a treatment modality for nevus sebaceus.

Weedon D. Weedon's Skin Pathology. Churchill Livingstone. 1997.
Fitzpatrick's Dermatology in General Medicine. 5th Edition. McGraw-Hill. 1999.

Commonly Used Terms

Skin Cancers

Internet Links

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Last Updated 3/4/2002

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DISEASE ASSOCIATIONS	CHARACTERIZATION
APLASIA CUTIS CONGENITA
Didymosis aplasticosebacea: coexistence of aplasia cutis congenita and nevus sebaceus may be explained as a twin spot phenomenon. Happle R, Konig A. Department of Dermatology, University Hospital Marburg, Germany.	Dermatology 2001;202(3):246-8 Abstract quote BACKGROUND: Co-occurrence of aplasia cutis congenita and nevus sebaceus has sometimes been observed. OBJECTIVE: We propose a genetic mechanism that may explain this coexistence of two different congenital skin disorders. Methods and RESULTS: We review 15 cases as reported in the literature and present an additional case. To explain the temporal and spatial proximity of the two skin lesions we advance the concept of twin spotting for which we propose the term didymosis (Greek didymos = twin). In an embryo heterozygous for two different recessive mutations localized on either of a pair of homologous chromosomes, an event of somatic recombination would occur at an early developmental stage, giving rise to two different cell clones homozygous for either mutation. CONCLUSION: The concept of didymosis aplasticosebacea is so far hypothetical. Future molecular research may show whether this concept holds true.
APOCRINE CARCINOMA
Tubular apocrine carcinoma arising in a nevus sebaceus of Jadassohn. Jacyk WK, Requena L, Sanchez Yus E, Judd MJ. Department of Dermatology, University of Pretoria, Republic of South Africa.	Am J Dermatopathol 1998 Aug;20(4):389-92 Abstract quote We present an example of tubular carcinoma that developed within a nevus sebaceus of Jadassohn on the scalp of a 53-year-old woman. The neoplasm showed features of sebaceous and apocrine differentiation. We review the literature about the malignant neoplasms arising in the nevus sebaceus of Jadassohn.
DESMOPLASTIC NEUROEPITHELIAL TUMOR
Desmoplastic neuroepithelial tumor of infancy in the nevus sebaceus syndrome: report of a unique constellation and review of the literature. Kopniczky Z, Kobor J, Maraz A, Vajtai I. Department of Neurosurgery, University of Szeged Health Sciences Center, Hungary.	Pathol Res Pract 2001;197(4):279-84 Abstract quote The nevus sebaceus syndrome (NSS) is a neurocutaneous disorder characterized by unilateral hyperplasia of skin appendages and skeletal hemihypertrophy, hemimegalencephaly, or hemiatrophy along with disabling seizures. Despite the proneness of the dermal stigmata to eventually undergo neoplastic transformation, the malformative lesions of the central nervous system rarely evolve into frank tumors. We present the case of a 10-year-old girl with left-sided sebaceus nevi, ipsilateral enlargement of the skull, and a desmoplastic neuroepithelial tumor (DNET) in the right fronto-parietal area of the brain. The tumor was removed by surgery. Histologically, it corresponded to a mitotically active small-cell anaplastic astrocytoma with genuine desmoplasia. Investigative methods included immunohistochemical positivity for glial fibrillary acidic protein, lack of expression of neuronal markers, and ultrastructural documentation of sheaths of basal lamina and collagen around tumor cells. A survey of the literature of brain tumors associated with NSS revealed two cases of histologically verified pilocytic astrocytomas, and one each of a choroid plexus papilloma, a mixed glioma, and a meningioma, as well as a subependymal giant cell astrocytoma--the latter possibly in an overlap syndrome of NSS and tuberous sclerosis. We hypothesize that the tumor described herein, one involving both atypical differentiation and enhanced growth potential, is paradigmatic of neuropathological events to be expected in the NSS.
ECCRINE SPIRADENOMA
Spiradenoma arising in a nevus sebaceus of Jadassohn: case report and literature review. Shapiro M, Johnson B Jr, Witmer W, Elenitsas R. University of Pennsylvania Medical Center, Department of Dermatology, Philadelphia 19104, USA.	Am J Dermatopathol 1999 Oct;21(5):462-7 Abstract quote Nevus sebaceus (NS) of Jadassohn is usually a verrucous plaque on the scalp or face that arises secondary to disordered development of epithelial, pilar, sebaceous, and apocrine structures. The emergence of neoplasia is a late stage in the natural history of NS. Although most neoplastic proliferations are benign, several malignant tumors have arisen in this lesion. We describe the first case of a benign spiradenoma arising in an NS on the scalp in a 72-year-old Caucasian woman. Reexcision was recommended to prevent the development of a second neoplastic process and to avoid the rare occurrence of a malignant transformation of the existing neoplasia. The patient declined reexcision and remains under observation. The spectrum of tumors arising in NS are described and are categorized according to behavior. Syringocystadenoma papilliferum is the most commonly observed benign growth, whereas basal cell carcinoma is the most frequently seen malignant process. The signs of tumor development (benign or malignant) within an NS are reviewed, and treatment recommendations are provided. The clinical course of rare and unique aggressive neoplasms originating in NS is summarized.
NEUROFIBROMATOSIS
Segmental neurofibromatosis in association with nevus sebaceus of Jadassohn. Lupton JR, Elgart ML, Sulica VI. The George Washington University Hospital, Washington, DC 20037, USA.	J Am Acad Dermatol 2000 Nov;43(5 Pt 2):895-7 Abstract quote We describe an unusual case involving the simultaneous occurrence of segmental neurofibromatosis (Type V NF) in a patient with a large nevus sebaceus of Jadassohn in the same physical distribution. Causative mechanisms of development of these 2 genetic disorders have not been definitively linked. Factors producing these diseases probably involve similar tissues at the same point in development because both have been reported in association with central nervous system anomalies and have been classified among the neurocutaneous syndromes. This is a case of a nevus sebaceus occurring in association with and in the same physical distribution as segmental NF. These disorders most likely represent a spectrum of disease within the phakomatoses.
OCULAR CHANGES
A new neurocutaneous syndrome: nevus sebaceus syndrome. Kucukoduk S, Ozsan H, Turanli AY, Dinc H, Selcuk M. Department of Pediatrics, Ondokuz Mayis University, Samsun, Turkey.	Cutis 1993 Jun;51(6):437-41 Abstract quote We describe a case of nevus sebaceus syndrome characterized by a linear sebaceous nevus, extending on the left half of the face from forehead to lower neck, including the auricle; alopecia on the temporoparietal region; generalized hypotonia; insufficiency of eyes in following moving objects and insufficiency in controlling the head; lipodermoid cysts in the left and right eyes; bilateral conjunctival masses; corneal vascularization in the right eye; coloboma of the left eyelid and right optic disc. T his is a rare case of a sebaceous nevus occurring concomitantly with optical and central nervous system abnormalities.
SEBACEOUS CARCINOMA
Sebaceous carcinoma, trichoblastoma, and sebaceoma with features of trichoblastoma in nevus sebaceus. Misago N, Kodera H, Narisawa Y. Division of Dermatology, Department of Internal Medicine, Saga Medical School, Saga, Japan.	Am J Dermatopathol 2001 Oct;23(5):456-62 Abstract quote A 73-year-old woman had a linear yellowish plaque on the upper part of her right ear since birth. She presented because of the sudden growth of a nodule within the plaque. The plaque was waxy and yellowish, arching around the upper part of the ear. A reddish to yellowish large nodule was seen within the central part of the arc-shaped plaque; in addition, a small pigmented nodule, a small skin-colored nodule, and a few pigmented papules were observed in the anterior half of the arched plaque. Histopathologic examination revealed the large nodule to be sebaceous carcinoma, the small pigmented nodule to be trichoblastoma, the small skin-colored nodule to be sebaceoma with the features of trichoblastoma, a few pigmented papules to be superficial trichoblastomas due to primitive follicular induction, and the linear yellowish plaque to be nevus sebaceus. Although our literature search revealed scanty reports of definite cases of sebaceous carcinoma in nevus sebaceus, the presented case demonstrated the occurrence of sebaceous carcinoma in nevus sebaceus. Malignant neoplasms occurring in nevus sebaceous seem to be extremely rare, but care should be taken when a large nodule suddenly grows in a lesion of nevus sebaceus, especially in older adults. The presented case also suggested a close relation between trichoblastoma and sebaceoma. The cytokeratin staining pattern could not distinguish between sebaceous and follicular neoplasms in our case.
SPECKLED LENTIGINOUS NEVUS
Phacomatosis pigmentokeratotica: speckled-lentiginous nevus in association with nevus sebaceus. Langenbach N, Hohenleutner U, Landthaler M. Department of Dermatology, University of Regensburg, Germany.	Dermatology 1998;197(4):377-80 Abstract quote We report a case of a congenital nevus sebaceus with numerous brown macules and papules in the left auricular region. In the same lesion, pigmented basal cell carcinomas developed later in life. Additionally, on the left side of the neck, both shoulders and the left arm, features of nevus spilus with melanocytic and blue nevi were present. Such a combination of nevus sebaceus with melanocytic lesions may be explained by the concept of twin spotting and represent another case of phacomatosis pigmentokeratotica.
TRICHOBLASTOMA
Trichoblastoma is the most common neoplasm developed in nevus sebaceus of Jadassohn: a clinicopathologic study of a series of 155 cases. Jaqueti G, Requena L, Sanchez Yus E. Department of Dermatology of Fundacion Jimenez Diaz, Universidad Autonoma, Madrid, Spain.	Am J Dermatopathol 2000 Apr;22(2):108-18 Abstract quote Nevus sebaceus of Jadassohn is a hamartoma that combines epidermal, follicular, sebaceous, and apocrine gland abnormalities. Classically, several types of cutaneous neoplasms have been associated with this hamartoma, with basal cell carcinoma being the most frequently described malignancy. We studied a series of 155 examples of nevus sebaceus of Jadassohn with clinicopathologic correlation. Several histopathologic changes related to the age of the patients were found. In our series, we could not identify any cases of authentic basal cell carcinoma. In contrast, several examples of primitive follicular induction and of trichoblastomas were seen. Other cutaneous hamartomas, hyperplasias, and neoplasms found in our series of nevus sebaceus of Jadassohn included syringocystadenoma papilliferum, sebomatricoma, apocrine gland cyst, poroma, different histopathologic variants of warts (classic warts, tricholemmoma, and desmoplastic tricholemmoma), primitive follicular induction, and ductal induction. In our series, no examples of malignant neoplasms were identified. On the basis of these findings, the classically recommended treatment for this hamartoma, which consists of early excision to prevent the development of malignancy, seems to be inappropriate.
Clear cell trichoblastoma in association with a nevus sebaceus. Tronnier M. Department of Dermatology, Medical University of Lubeck, Lubeck, Germany.	Am J Dermatopathol 2001 Apr;23(2):143-5 Abstract quote Nevus sebaceus is a hamartoma that is frequently associated with various neoplasms. Among the neoplasms observed in sebaceus nevi, trichoblastomas are the most common. The present case, to my knowledge, is the first description of a clear cell variant of trichoblastoma.

LABORATORY/RADIOLOGIC/ OTHER TESTS	CHARACTERIZATION
RADIOLOGIC
Proton magnetic resonance spectroscopy of linear nevus sebaceus syndrome. Kruse B, Pouwels PJ, Christen HJ, Frahm J, Hanefeld FA. Abteilung Kinderheilkunde; Schwerpunkt Neuropadiatrie; Georg-August-Universitat, Gottingen, Germany.	Pediatr Neurol 1998 Feb;18(2):176-80 Abstract quote Cerebral metabolites of a patient with linear nevus sebaceus syndrome and hemimegalencephaly were determined at 18 and 30 months of age by localized proton magnetic resonance spectroscopy. Clinically, the patient suffered from hemiparesis and epileptic seizures. At 18 months of age, spectroscopy of the enlarged hemisphere revealed decreased N-acetylaspartate mainly in parietal white matter relative to the unaffected hemisphere. One year later, white matter studies indicated both reduced N-acetylaspartate and elevated myoinositol. In insular gray matter the previously normal concentrations of creatine, choline-containing compounds, myoinositol, and glutamine were increased. The findings are consistent with mild neuroaxonal loss or damage (white matter) and glial proliferation (cortical gray and white matter) of the affected hemisphere. The metabolic disturbances indicate disease progression but are less pronounced than in older patients with hemimegalencephaly.
Cortical reorganization in linear nevus sebaceous syndrome: a multimodality neuroimaging study. Levy-Reis I, Casasanto DJ, Gonzalez JB, Alsop DC, Glosser G, Maldjan JA, French J, Detre JA. Department of Neurology, University of Pennsylvania, USA.	J Neuroimaging 2000 Oct;10(4):225-8 Abstract quote The authors report the findings of multimodal structural, functional, and metabolic imaging in a patient with linear nevus sebaceous syndrome, intractable seizures, and right megalencephaly. Despite nearly continuous paroxysmal electrical activity from the megalencephalic region, imaging studies suggested nonfunctional tissue in this region with reorganization of cortical function to the unaffected ipsilateral hemisphere. Hemispherectomy has been successfully performed in previous patients; however, it could have led to marked left hemiparesis with significant functional morbidity in this patient because of ipsilateral reorganization of the primary motor cortex.

PROGNOSIS AND TREATMENT	CHARACTERIZATION
PROGNOSTIC FACTORS
MALIGNANCIES
Nevus sebaceus of Jadassohn: the head and neck manifestations. Hagan WE.	Laryngoscope 1987 Aug;97(8 Pt 1):909-14 Abstract quote The nevus sebaceus of Jadassohn (SNJ) is a congenitally-occurring, hamartomatous disorder of the skin and its adnexa of infrequent occurrence. This presentation of five cases emphasizes the smooth, waxy, yellow-brown lesion's progression into a thickened sebaceous tumor of premalignant predilection. The incidence of neoplastic degeneration of these hamartomatous nevi may be as high as 30% with the capacity of metastasis occasionally reported. Because of malignancy risks as well as cosmetic considerations, early surgical removal is recommended. Previously unreported problems of dysphagia and malnutrition secondary to pulsion diverticulum at the esophageal inlet and cleft palate, obliterative aural stenosis with associated conductive hearing loss are documented. Regardless of SNJ's occurrence as either an isolated lesion or as the fully developed syndrome, including mental retardation and epilepsy, this congenital malformation of the skin, its hair, and sebaceous glands presents rare and histologically intriguing problems for the practitioner.
Tumors arising in nevus sebaceus: A study of 596 cases. Cribier B, Scrivener Y, Grosshans E. Laboratoire d'Histopathologie Cutanee, Clinique Dermatologique des Hopitaux Universitaires de Strasbourg, France.	J Am Acad Dermatol 2000 Feb;42(2 Pt 1):263-8 Abstract quote BACKGROUND: Prophylactic surgical excision of nevus sebaceus (NS) during childhood is often recommended because various neoplasms can occur on NS. The proportion of malignant tumors occurring on NS is highly variable among the published series, and there are controversies on the nature of these neoplasms because many of the previously described basal cell carcinomas could actually be trichoblastomas, which are benign follicular tumors. OBJECTIVE: We retrospectively analyzed all cases of NS of our collection, excised during the period from 1932 through 1998, and recorded all associated epithelial and nonepithelial changes. We especially differentiated basal cell carcinomas from trichoblastomas by silhouette analysis and examination of the stroma. These findings were analyzed according to gender, age, and localization. METHODS: Microscopic analysis of NS by two examiners was performed independently of clinical data. RESULTS: A total of 596 cases were included from 290 females and 306 males, mean age 25.4 years (range, 1 month to 87 years); 232 were excised in children younger than 16 years. NSs were located on the scalp in 49.8% of cases. Basal cell carcinomas were found in 5 cases (0.8%, mean age 39.3 years) and benign tumors in 81 cases (13.6%, mean age 46.3 years). Syringocystadenoma papilliferum (n = 30, 15 males, 15 females) and trichoblastoma (n = 28, 7 males, 21 females) were the most frequent benign tumors. NS with associated tumors were located on the scalp in 79% of cases. Only 4 benign tumors (1.7%) and 2 warts were observed in patients younger than 16 years. Various types of epithelial hyperplasia were noted that could not be considered neoplasms, as well as epidermal and apocrine cysts. CONCLUSION: The rate of malignant tumors arising on NS was very low and we did not observe such cases in children, who had associated benign tumors in only 1.7% of cases. Benign neoplasms were common and most of them occurred on the scalp; this was not a bias resulting from a longer duration before surgery. Trichoblastoma and not basal cell carcinoma was the most frequent follicular tumor associated with NS and showed a striking female predominance. Most trichoblastomas had previously been misdiagnosed but could actually be easily recognized by typical histologic features. Because most tumors occurred in adults older than 40 years, our study suggests that prophylactic surgery in young children is of uncertain benefit. Clinical follow-up is probably sufficient, and even those cases with clinical changes often proved to be benign tumors or warts.
Basal cell carcinoma originating from a nevus sebaceus on the scalp of a 7-year-old boy. Turner CD, Shea CR, Rosoff PM. Division of Pediatric Hematology-Oncology, Duke University Medical Center, Durham, North Carolina, USA.	J Pediatr Hematol Oncol 2001 May;23(4):247-9 Abstract quote Basal cell carcinoma (BCC) occurs rarely in children and is most often associated with an underlying condition that predisposes patients to the development of malignancy. There have been numerous reports of BCC developing after puberty in nevus sebaceus; however, such occurrences have rarely been described in children. We report a 7-year-old boy with BCC forming in a nevus sebaceus.
Malignant transformation in congenital sebaceous naevi in childhood. Dunkin CS, Abouzeid M, Sarangapani K. Department of Plastic and Reconstructive Surgery, Middlesbrough General Hospital, UK.	J R Coll Surg Edinb 2001 Oct;46(5):303-6 Abstract quote Sebaceous naevi are uncommon congenital skin lesions with a well-recognised potential for neoplastic change. They should be considered premalignant lesions as malignant degeneration, most commonly basal cell carcinoma and squamous cell carcinoma, occurs with a lifetime risk of between 5% and 22%. This incidence is equal to that of actinic keratosis and exceeds that of oral leukoplakia. Such change, however, is rare before puberty. Basal cell carcinoma may develop in children with naevoid basal cell carcinoma syndrome, xeroderma pigmentosum and rarely de novo but sebaceous naevus is the only solitary lesion in childhood associated with the development of basal cell carcinoma. We present two cases of malignant transformation in a congenital sebaceous naevus occurring in childhood and review the literature and discuss the evidence upon which to base management guidelines.
TREATMENT
LASER
Linear nevus sebaceus of Jadassohn treated with the carbon dioxide laser. Ashinoff R. Ronald O. Perelman Department of Dermatology, New York University Medical Center, New York.	Pediatr Dermatol 1993 Jun;10(2):189-91 Abstract quote A 10-year-old boy from Guiana was born with a linear nevus sebaceus covering his entire nose from the glabella area to the tip. Cosmetic appearance, which was the major concern of the patient and his family, was greatly improved by the use of the carbon dioxide (CO2) laser. The CO2 laser has not been reported previously as a treatment modality for nevus sebaceus.

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
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EPIDEMIOLOGY	CHARACTERIZATION
SYNONYMS	Nevus Sebaceus of Jadassohn

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
GENERAL
VARIANTS
CEREBRIFORM
Cerebriform sebaceous nevus. Ramesh A, Murugusundaram S, Vittel K, Kumar S, Janaki VR, Boopalraj JM. Department of Dermatology, Madras Medical College, India.	Int J Dermatol 1998 Mar;37(3):220 Abstract quote A 20-year-old man presented with a well-defined, soft to firm, freely mobile pinkish-yellow plaque of 9.5 cm over the right parieto-occipital region with a typical cerebriform appearance. In total, nine folds were present with short black terminal hair in the sulci area. There was no follicular plugging. Skeletal survey and neurologic and ophthalmologic assessments were normal. Skin biopsy was compatible with sebaceous nevus showing mature sebaceous glands in the upper dermis and mature apocrine glands in the lower dermis with malformed hair germ.
FAMILIAL
Familial occurrence of nevus sebaceus of Jadassohn: another case of paradominant inheritance? Laino L, Steensel MA, Innocenzi D, Camplone G. Department of Dermatology, Policlinico Umberto I, University "La Sapienza", Rome, Italy.	Eur J Dermatol 2001 Mar-Apr;11(2):97-8 Abstract quote We describe two sibs (a boy and a girl) suffering from linear nevus sebaceus of Jadassohn. The parents are not affected. This rare pattern of familial occurrence prompts us to suggest that these sibs represent a case of paradominant inheritance of a mosaic disorder.