Lentigo

Background

This is a common and benign pigmented lesion of the skin, composed of an increase in melanocytes at the dermal-epidermal junction. It is closely related to the melanocytic nevus and indeed, some junctional nevi share histologic features with lentigos, occasionally called jentigos.

OUTLINE

Epidemiology

Disease Associations

Pathogenesis

Laboratory/Radiologic/Other Diagnostic Testing

Gross Appearance and Clinical Variants

Histopathological Features and Variants

Special Stains/
Immunohistochemistry/
Electron Microscopy

Differential Diagnosis

Prognosis

Treatment

Commonly Used Terms

Internet Links

EPIDEMIOLOGY CHARACTERIZATION

INCIDENCE Common

AGE RANGE-MEDIAN All

SEX (M:F)
Both

DISEASE ASSOCIATIONS CHARACTERIZATION

CARNEY COMPLEX

Carney complex: in a patient with multiple blue naevi and lentigines, suspect cardiac myxoma.

Bleasel NR, Stapleton KM.

Department of Dermatology, Royal Hobart Hospital, Tasmania, Australia.
Australas J Dermatol 1999 Aug;40(3):158-60 Abstract quote
Carney complex is characterized by spotty pigmentation (blue naevi and lentigines), myxomas (cardiac, cutaneous, mammary), endocrine over-activity (Cushing's syndrome, acromegaly), testicular tumours, and schwannomas.

We report a male with multiple blue naevi, lentigines, testicular large cell calcifying Sertoli-cell tumour and four cardiac myxomas. The myxomas caused two cerebrovascular accidents and a myocardial infarction. All patients with multiple blue naevi or lentigines should be investigated for the life-threatening association of cardiac myxomas.

COWDEN'S SYNDROME

Genital lentigines in a 6-year-old boy with a family history of Cowden's disease: clinical and genetic evidence of the linkage between Bannayan-Riley-Ruvacalba syndrome and Cowden's disease.

Blum RR, Rahimizadeh A, Kardon N, Lebwohl M, Wei H.

Department of Dermatology, Mount Sinai Medical Center, New York, New York, USA 10029, USA.
J Cutan Med Surg 2001 May-Jun;5(3):228-30 Abstract quote
BACKGROUND: In 1997, it was reported that a PTEN gene deletion, a common genetic mutation in Cowden's disease (CD), was identified in a patient with Bannayan-Riley-Ruvacalba (BRR), suggesting that the two diseases were allelic. However, the clinical overlap between the two diseases has largely remained unclear.

OBJECTIVE: To confirm the genetic and clinical association in a family segregating both CD and BRR.

METHODS: Clinical evaluation and genetic analysis using a denaturing gradient gel electrophoresis (DGGE), temporal temperature gradient electrophoresis (TTGE), and DNA sequencing techniques.

RESULTS: Our patient presents with typical BRR clinical manifestations, including multiple lentigines on his penis, while his mother presents with typical manifestations of CD, including multiple malignancies. Genetic analyses of leukocytes from the patient and his mother showed mutations in exon 8 that was identified as the presumably truncating mutation R335X.

CONCLUSION: This report provides clinical evidence that both BRR and CD are closely related and confirms the PTEN gene mutation in BRR and CD patients segregating in the same family, thus confirming the genetic linkage between the two genodermatoses.

LEOPARD SYNDROME

Leopard syndrome.

Tong KL, Ding ZP, Chua T.

Department of Cardiology, National Heart Centre, Singapore.
Singapore Med J 2001 Jul;42(7):328-31 Abstract quote
The Leopard syndrome is a complex of multisystemic congenital abnormalities characterised by lentiginosis, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth and deafness (sensorineural). Hypertrophic cardiomyopathy, though not included in the mnemonic, is often associated.

Although the Leopard syndrome is rare, it is important to recognise it since it can be associated with serious cardiac disease. It is advisable to follow up patients with Leopard syndrome for new onset of cardiac abnormalities and to monitor the progression of existing cardiac disease.

We present a case report and review of the literature of this syndrome.

NEUROFIBROMATOSIS

Lentiginous macules and patches of neurofibromatosis (an approach to better terminology).

Amer M, Mostafa FF, Nasr AN.

Department of Dermatology and Pathology, University of Zagazig, Faculty of Medicine, Egypt.

J Eur Acad Dermatol Venereol 2001 Jan;15(1):39-42 Abstract quote
BACKGROUND AND OBJECTIVES: Freckles (ephelides) are small, light brown macules of sun-exposed areas in fair-skinned subjects. On the other hand, freckle-like pigmentation of the axilla is a highly characteristic feature of neurofibromatosis. To what extent (clinically and pathologically) are the two pigmentary defects similar? And to what extent are cafe-au-lait patches and freckle-like lesions similar pathologically?

SUBJECTS AND METHODS: Ten cases of neurofibromatosis and 10 cases of freckles were examined clinically. Two biopsies were taken from the former; one obtained from an axillary freckle-like lesion, and the other from a cafe-au-lait patch. One biopsy only was taken from freckles. The biopsies were processed for haematoxylin and eosin, silver stain and transmission electron microscopy.

RESULTS: Obvious differences were detected between freckles (ephelides) and freckle-like lesions in cases of neurofibromatosis. Cafe-au-lait patches and freckle-like lesions showed the same pathological changes of lentigo simplex, with increased melanin pigment from the basal layer up to the stratum corneum, moderate elongation of the rete ridges and mild inflammatory infiltrate intermingled with melanophages. Electron microscopy revealed an increase in melanocyte number and the presence of giant melanin granules in freckle-like pigmentation as well as cafe-au-lait patches. These ultrastructural freckles (ephelides) showed an increase in activity but not the number of melanocytes.

CONCLUSIONS: The term freckle-like should be changed to lentiginous macules of neurofibromatosis. On the other hand, the cafe-au-lait patches should be considered as lentiginous patches. Freckles should be restricted to sun-exposed areas in fair-skinned persons only.

PATHOGENESIS CHARACTERIZATION

APOPTOSIS

Hamartoma and lentiginosis syndromes: clinical and molecular aspects.

Marsh DJ, Stratakis CA.

Cancer Genetics, Kolling Institute of Medical Research, Royal North Shore Hospital, and Sydney University, Sydney, Australia.
Front Horm Res 2001;28:167-213 Abstract quote
The classic hamartoma syndromes and the related conditions discussed in this chapter show varying degrees of phenotypic and genetic overlap. Knowledge of the susceptibility genes underlying their phenotypes has provided additional information for the classification of these syndromes.

Germline PTEN mutations appear to cause both CS and BRR. These two syndromes are therefore likely to be different manifestations of a single disease with variable expression. It has been suggested that PTEN mutation-positive CS and BRR should be grouped as a single entity for clinical purposes and classified as the 'PTEN hamartoma-tumour syndrome' [111]. Germline PTEN mutations are unlikely to cause JPS. However, germline SMAD4 mutation, especially a well-described 4-bp deletion, can be used to confirm a clinical diagnosis of JPS. Like the hamartoma syndromes, the lentiginoses also show substantial clinical overlap; it remains to be seen whether this is reflected in the molecular pathways that are involved in the pathogenesis of these syndromes. Given that the degree and type of cancer susceptibility between the hamartoma and lentiginosis syndromes is different, clarification of these syndromes at the molecular level is predicted to allow directed cancer surveillance.

The molecular story is still evolving with regards to aspects of genetic heterogeneity, signalling pathways and the manner in which these hamartoma genes function in the development of their respective syndromes. It is likely that in all of these syndromes, tumours develop against a background created by loss of the growth-suppressive function of their susceptibility gene via mechanisms including disruption of the cell cycle and the activation of anti-apoptotic pathways.

KERATINOCYTES

Perilesional vs. lesional skin changes in senile lentigo.

Cario-Andre M, Lepreux S, Pain C, Nizard C, Noblesse E, Taieb A.

INSERM E217, University V. Segalen, Bordeaux, France

J Cutan Pathol. 2004 Jul;31(6):441-7. Abstract quote

BACKGROUND: Senile lentigo (SL) is a common component of photoaged skin. It is characterized by hyperpigmented macules which affect chronically irradiated skin mostly after 50 years of age. This study was undertaken to assess the basic morphology of SL on dorsum of hands.

METHODS: A systematic comparison between lesional vs. perilesional skin using immunohistochemistry and electron microscopy was done to detect precursor lesions of SL and to determine whether melanocytes or keratinocytes were first affected in the evolution of lesions.

RESULTS: In 12 cases studied, the main findings show that clusters of perilesional keratinocytes accumulate melanin in large melanosomial complexes, and that melanocytes counts are increased respective to total length of section in lesional skin, but the increment is probably due to the development of characteristic epidermal rete ridges. Melanocytes had overall a normal ultrastructure, with mostly quiescent features in perilesional skin and melanosomial transport seeming more active in lesional skin.

CONCLUSIONS: Our data indicate that SL may represent a loss of epidermal melanin unit homeostasis due to chronic irradiation, where keratinocytic changes predominate over melanocytic changes. We hypothesize that abnormal pigment retention in keratinocytes is the primary defect in SL, which may partly explain the therapeutic effect of retinoids.

LABORATORY/
RADIOLOGIC/
OTHER TESTS
CHARACTERIZATION

RADIOLOGIC

LABORATORY MARKERS

EPILUMINESCENCE MICROSCOPY

Detection of a Novel Pigment Network Feature in Reticulated Black Solar Lentigo by High-Resolution Epiluminescence Microscopy

Norbert Haas, M.D.; Barbara Hermes, M.D.; Beate M. Henz, M.D.
Am J Dermatopathol 2002; 24(3):213-217 Abstract quote

Epiluminescence light microscopy (ELM) of pigmented skin lesions has led to a catalog of pigment network (PN) features. The objective of this study was to determine whether high-resolution ELM detects additional pigment structures not seen with conventional ELM.

Epiluminescence light microscopy was performed by placing the lens of a standard light microscope directly on the skin surface, with resulting enhanced optical resolution compared with ELM systems currently in general use. Eight reticulated black solar lentigines were studied. All lesions were viewed and analyzed using dermatoscopic criteria for the PN. In addition, they were all photographed, excised, and examined histologically. Two subtypes of black solar lentigines could be distinguished using generally accepted dermatoscopic criteria for the PN. Furthermore, a new pigment structure was detected, namely, pigment spots of equal color, shape, and size, which were regularly superimposed on and juxtaposed to the PN. Clinicopathologic correlation showed these spots to represent individual hyperpigmented corneocytes. Because such cells result from physiologic excessive pigment translocation via the epidermal melanocytic unit, we called them pigmented corneocytes. Pigmented corneocytes were seen in seven of eight black solar lentigines.

The ELM technique presented here allows for more detailed analysis and classification of the PN components. Pigmented corneocytes are proposed as an additional dermatoscopic criterion.

GROSS APPEARANCE/
CLINICAL VARIANTS CHARACTERIZATION

GENERAL

VARIANTS

OCULAR

Partial unilateral lentiginosis with ocular involvement.

Schaffer JV, Lazova R, Bolognia JL.

Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
J Am Acad Dermatol 2001 Feb;44(2 Suppl):387-90 Abstract quote
Partial unilateral lentiginosis (PUL) is an unusual pigmentary disorder characterized by numerous lentigines grouped within an area of normal skin; the pigmented macules are often in a segmental distribution with a sharp demarcation at the midline.

We report the first case of ocular involvement in a patient with this diagnosis. The patient, a 30-year-old Peruvian woman, had multiple brown macules on the left upper face in primarily a V1 and V2 distribution with a sharp demarcation at the midline of the forehead. The lesions first appeared near the hairline when she was 5 years of age, and then began to extend onto the face.

She also had a discrete area of brown pigmentation on the left lateral bulbar conjunctiva. Because the patient had been previously diagnosed by several dermatologists as having either a speckled lentiginous nevus or a nevus of Ota, we draw attention to the entity PUL and the possibility of ocular involvement.

ORAL

The congenital lingual melanotic macule.

Dohil MA, Billman G, Pransky S, Eichenfield LF.

Pediatric and Adolescent Dermatology, Department of Pathology, and Pediatric Otolaryngology, Children's Hospital, San Diego, Calif.

Arch Dermatol. 2003 Jun;139(6):767-70 Abstract quote
BACKGROUND: Circumscribed oral melanotic macules in adults are a well-defined entity. Congenital oral melanotic macules, however, are rare and not well characterized. We report 5 cases of congenital lingual melanotic lesions with consistent clinical and histologic features.

OBSERVATIONS: Congenital lingual melanotic macules presented in all cases at birth, followed by proportional growth. Clinical findings were well-circumscribed, brown, single or multiple macules on the tongue, 2 to 5 mm in size, without history of bleeding, ulceration, or trauma. Family history was negative for similar pigmented lesions. A literature review showed only 2 previous clinical case reports with similar features. Histopathologic examination showed increased melanin pigmentation in the basal epidermal layer with varying degrees of overlying hyperkeratosis and subepidermal pigment-laden macrophages. No appreciable increase in melanocyte number, junctional nests of melanocytes, or cell atypia was noted. Two retrospective histopathology reviews mention 4 corresponding cases but report no clinical data.

Conclusion The congenital lingual melanotic macule represents a clinically distinct, benign, pigmented oral melanotic lesion, and may be more common than the literature suggests.

UNILATERAL

Extensive partial unilateral lentiginosis.

Romiti R, Harnache JDI, Neto CF, Kreuter A, Altmeyer P, Jansen T.

Department of Dermatology, University of Sao Paulo, Brazil.
J Dermatol 2001 Sep;28(9):490-2 Abstract quote
Partial unilateral lentiginosis is a rare pigmentary disorder characterized by multiple lentigines on otherwise normal skin affecting one side of the body. The histology is that of a lentigo.

We report two young men with an extensive form of partial unilateral lentiginosis affecting the skin. No systemic abnormalities could be identified.

HISTOLOGICAL TYPES CHARACTERIZATION

GENERAL Increase in melanocytes and pigment within elongated rete ridges

VARIANTS

SPECIAL STAINS/
IMMUNOPEROXIDASE/
OTHER CHARACTERIZATION

SPECIAL STAINS Fontana Masson positive

IMMUNOPEROXIDASE Melanocytes are S100 positive

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES

DYSPLASTIC NEVUS

MELANOMA

PROGNOSIS AND TREATMENT CHARACTERIZATION

PROGNOSTIC FACTORS Benign

TREATMENT Simple excision

Weedon D. Weedon's Skin Pathology. Churchill Livingstone. 1997.
Fitzpatrick's Dermatology in General Medicine. 5th Edition. McGraw-Hill. 1999.
Robbins Pathologic Basis of Disease. Sixth Edition. WB Saunders 1999.

Commonly Used Terms

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Special Stains
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Internet Links

Last Updated 7/12/2004

DISEASE ASSOCIATIONS	CHARACTERIZATION
CARNEY COMPLEX
Carney complex: in a patient with multiple blue naevi and lentigines, suspect cardiac myxoma. Bleasel NR, Stapleton KM. Department of Dermatology, Royal Hobart Hospital, Tasmania, Australia.	Australas J Dermatol 1999 Aug;40(3):158-60 Abstract quote Carney complex is characterized by spotty pigmentation (blue naevi and lentigines), myxomas (cardiac, cutaneous, mammary), endocrine over-activity (Cushing's syndrome, acromegaly), testicular tumours, and schwannomas. We report a male with multiple blue naevi, lentigines, testicular large cell calcifying Sertoli-cell tumour and four cardiac myxomas. The myxomas caused two cerebrovascular accidents and a myocardial infarction. All patients with multiple blue naevi or lentigines should be investigated for the life-threatening association of cardiac myxomas.
COWDEN'S SYNDROME
Genital lentigines in a 6-year-old boy with a family history of Cowden's disease: clinical and genetic evidence of the linkage between Bannayan-Riley-Ruvacalba syndrome and Cowden's disease. Blum RR, Rahimizadeh A, Kardon N, Lebwohl M, Wei H. Department of Dermatology, Mount Sinai Medical Center, New York, New York, USA 10029, USA.	J Cutan Med Surg 2001 May-Jun;5(3):228-30 Abstract quote BACKGROUND: In 1997, it was reported that a PTEN gene deletion, a common genetic mutation in Cowden's disease (CD), was identified in a patient with Bannayan-Riley-Ruvacalba (BRR), suggesting that the two diseases were allelic. However, the clinical overlap between the two diseases has largely remained unclear. OBJECTIVE: To confirm the genetic and clinical association in a family segregating both CD and BRR. METHODS: Clinical evaluation and genetic analysis using a denaturing gradient gel electrophoresis (DGGE), temporal temperature gradient electrophoresis (TTGE), and DNA sequencing techniques. RESULTS: Our patient presents with typical BRR clinical manifestations, including multiple lentigines on his penis, while his mother presents with typical manifestations of CD, including multiple malignancies. Genetic analyses of leukocytes from the patient and his mother showed mutations in exon 8 that was identified as the presumably truncating mutation R335X. CONCLUSION: This report provides clinical evidence that both BRR and CD are closely related and confirms the PTEN gene mutation in BRR and CD patients segregating in the same family, thus confirming the genetic linkage between the two genodermatoses.
LEOPARD SYNDROME
Leopard syndrome. Tong KL, Ding ZP, Chua T. Department of Cardiology, National Heart Centre, Singapore.	Singapore Med J 2001 Jul;42(7):328-31 Abstract quote The Leopard syndrome is a complex of multisystemic congenital abnormalities characterised by lentiginosis, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth and deafness (sensorineural). Hypertrophic cardiomyopathy, though not included in the mnemonic, is often associated. Although the Leopard syndrome is rare, it is important to recognise it since it can be associated with serious cardiac disease. It is advisable to follow up patients with Leopard syndrome for new onset of cardiac abnormalities and to monitor the progression of existing cardiac disease. We present a case report and review of the literature of this syndrome.
NEUROFIBROMATOSIS
Lentiginous macules and patches of neurofibromatosis (an approach to better terminology). Amer M, Mostafa FF, Nasr AN. Department of Dermatology and Pathology, University of Zagazig, Faculty of Medicine, Egypt.	J Eur Acad Dermatol Venereol 2001 Jan;15(1):39-42 Abstract quote BACKGROUND AND OBJECTIVES: Freckles (ephelides) are small, light brown macules of sun-exposed areas in fair-skinned subjects. On the other hand, freckle-like pigmentation of the axilla is a highly characteristic feature of neurofibromatosis. To what extent (clinically and pathologically) are the two pigmentary defects similar? And to what extent are cafe-au-lait patches and freckle-like lesions similar pathologically? SUBJECTS AND METHODS: Ten cases of neurofibromatosis and 10 cases of freckles were examined clinically. Two biopsies were taken from the former; one obtained from an axillary freckle-like lesion, and the other from a cafe-au-lait patch. One biopsy only was taken from freckles. The biopsies were processed for haematoxylin and eosin, silver stain and transmission electron microscopy. RESULTS: Obvious differences were detected between freckles (ephelides) and freckle-like lesions in cases of neurofibromatosis. Cafe-au-lait patches and freckle-like lesions showed the same pathological changes of lentigo simplex, with increased melanin pigment from the basal layer up to the stratum corneum, moderate elongation of the rete ridges and mild inflammatory infiltrate intermingled with melanophages. Electron microscopy revealed an increase in melanocyte number and the presence of giant melanin granules in freckle-like pigmentation as well as cafe-au-lait patches. These ultrastructural freckles (ephelides) showed an increase in activity but not the number of melanocytes. CONCLUSIONS: The term freckle-like should be changed to lentiginous macules of neurofibromatosis. On the other hand, the cafe-au-lait patches should be considered as lentiginous patches. Freckles should be restricted to sun-exposed areas in fair-skinned persons only.

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
GENERAL
VARIANTS
OCULAR
Partial unilateral lentiginosis with ocular involvement. Schaffer JV, Lazova R, Bolognia JL. Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.	J Am Acad Dermatol 2001 Feb;44(2 Suppl):387-90 Abstract quote Partial unilateral lentiginosis (PUL) is an unusual pigmentary disorder characterized by numerous lentigines grouped within an area of normal skin; the pigmented macules are often in a segmental distribution with a sharp demarcation at the midline. We report the first case of ocular involvement in a patient with this diagnosis. The patient, a 30-year-old Peruvian woman, had multiple brown macules on the left upper face in primarily a V1 and V2 distribution with a sharp demarcation at the midline of the forehead. The lesions first appeared near the hairline when she was 5 years of age, and then began to extend onto the face. She also had a discrete area of brown pigmentation on the left lateral bulbar conjunctiva. Because the patient had been previously diagnosed by several dermatologists as having either a speckled lentiginous nevus or a nevus of Ota, we draw attention to the entity PUL and the possibility of ocular involvement.
ORAL
The congenital lingual melanotic macule. Dohil MA, Billman G, Pransky S, Eichenfield LF. Pediatric and Adolescent Dermatology, Department of Pathology, and Pediatric Otolaryngology, Children's Hospital, San Diego, Calif.	Arch Dermatol. 2003 Jun;139(6):767-70 Abstract quote BACKGROUND: Circumscribed oral melanotic macules in adults are a well-defined entity. Congenital oral melanotic macules, however, are rare and not well characterized. We report 5 cases of congenital lingual melanotic lesions with consistent clinical and histologic features. OBSERVATIONS: Congenital lingual melanotic macules presented in all cases at birth, followed by proportional growth. Clinical findings were well-circumscribed, brown, single or multiple macules on the tongue, 2 to 5 mm in size, without history of bleeding, ulceration, or trauma. Family history was negative for similar pigmented lesions. A literature review showed only 2 previous clinical case reports with similar features. Histopathologic examination showed increased melanin pigmentation in the basal epidermal layer with varying degrees of overlying hyperkeratosis and subepidermal pigment-laden macrophages. No appreciable increase in melanocyte number, junctional nests of melanocytes, or cell atypia was noted. Two retrospective histopathology reviews mention 4 corresponding cases but report no clinical data. Conclusion The congenital lingual melanotic macule represents a clinically distinct, benign, pigmented oral melanotic lesion, and may be more common than the literature suggests.
UNILATERAL
Extensive partial unilateral lentiginosis. Romiti R, Harnache JDI, Neto CF, Kreuter A, Altmeyer P, Jansen T. Department of Dermatology, University of Sao Paulo, Brazil.	J Dermatol 2001 Sep;28(9):490-2 Abstract quote Partial unilateral lentiginosis is a rare pigmentary disorder characterized by multiple lentigines on otherwise normal skin affecting one side of the body. The histology is that of a lentigo. We report two young men with an extensive form of partial unilateral lentiginosis affecting the skin. No systemic abnormalities could be identified.

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Special Stains/ Immunohistochemistry/ Electron Microscopy
Differential Diagnosis
Prognosis
Treatment
Commonly Used Terms
Internet Links

EPIDEMIOLOGY	CHARACTERIZATION
INCIDENCE	Common
AGE RANGE-MEDIAN	All
SEX (M:F)	Both

LABORATORY/ RADIOLOGIC/ OTHER TESTS	CHARACTERIZATION
RADIOLOGIC
LABORATORY MARKERS
EPILUMINESCENCE MICROSCOPY
Detection of a Novel Pigment Network Feature in Reticulated Black Solar Lentigo by High-Resolution Epiluminescence Microscopy Norbert Haas, M.D.; Barbara Hermes, M.D.; Beate M. Henz, M.D.	Am J Dermatopathol 2002; 24(3):213-217 Abstract quote Epiluminescence light microscopy (ELM) of pigmented skin lesions has led to a catalog of pigment network (PN) features. The objective of this study was to determine whether high-resolution ELM detects additional pigment structures not seen with conventional ELM. Epiluminescence light microscopy was performed by placing the lens of a standard light microscope directly on the skin surface, with resulting enhanced optical resolution compared with ELM systems currently in general use. Eight reticulated black solar lentigines were studied. All lesions were viewed and analyzed using dermatoscopic criteria for the PN. In addition, they were all photographed, excised, and examined histologically. Two subtypes of black solar lentigines could be distinguished using generally accepted dermatoscopic criteria for the PN. Furthermore, a new pigment structure was detected, namely, pigment spots of equal color, shape, and size, which were regularly superimposed on and juxtaposed to the PN. Clinicopathologic correlation showed these spots to represent individual hyperpigmented corneocytes. Because such cells result from physiologic excessive pigment translocation via the epidermal melanocytic unit, we called them pigmented corneocytes. Pigmented corneocytes were seen in seven of eight black solar lentigines. The ELM technique presented here allows for more detailed analysis and classification of the PN components. Pigmented corneocytes are proposed as an additional dermatoscopic criterion.

HISTOLOGICAL TYPES	CHARACTERIZATION
GENERAL	Increase in melanocytes and pigment within elongated rete ridges
VARIANTS

SPECIAL STAINS/ IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
SPECIAL STAINS	Fontana Masson positive
IMMUNOPEROXIDASE	Melanocytes are S100 positive

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
DYSPLASTIC NEVUS
MELANOMA

PROGNOSIS AND TREATMENT	CHARACTERIZATION
PROGNOSTIC FACTORS	Benign
TREATMENT	Simple excision