Olfactory Neuroblastoma

PATHOGENESIS

SPERM PROTEIN 17

Sperm protein 17 expression defines 2 subsets of primary esthesioneuroblastoma. Bumm K, Grizzi F, Franceschini B, Koch M, Iro H, Wurm J, Ceva-Grimaldi G, Dimmler A, Cobos E, Dioguardi N, Sinha UK, Kast WM, Chiriva-Internati M. Department of Otorhinolaryngology, Head and Neck Surgery, Friedrich-Alexander-University Erlangen-Nuremberg, 91054 Erlangen, Germany.

Hum Pathol. 2005 Dec;36(12):1289-93. Abstract quote Esthesioneuroblastomas (ENBs) are rare malignant tumors of the nasal vault, the origin, diagnosis, and management of which are still subjects of discussion. That there is no related prognostic factor or generally recognized therapeutic regimen highlights the need for further analyses of its underlying biologic features and investigations of new marker proteins that allow more reliable clinical testing. We here show that sperm protein 17 (Sp17) is expressed in the ciliated cells of the normal olfactory epithelium and in a proportion of primary ENB lesions. We found an association between Sp17 expression and metastases at relapse (P = .035), chromogranin expression (P = .014), and a female sex prevalence. A statistically nonsignificant relation was found between Sp17 and S-100, synaptophysin, and neurofilament expression. No correlation was also found between Sp17 expression and the proliferative capacity of the lesion that was evaluated by Ki-67 immunohistochemistry. The results of this study show the usefulness of Sp17 as a means of discriminating 2 subsets of primary ENB lesions and seem to suggest the existence of 2 distinct cell pathways in their origin and development.

HISTOLOGICAL TYPES

CHARACTERIZATION

GENERAL

Under the microscope, these tumors have irregular nests of small hyperchromatic cells separated by stroma. A second less common pattern is diffuse sheets of cells with a prominent background of capillaries and little intervening stroma. The cells are small round blue cells with hyperchromatic nuclei and a high nuclear-cytoplasmic ratio. There are variable mitotic figures.

There is a distinct fibrillary background composed of neuronal cell processes. Flexner-type rosettes and Homer Wright-type pseudorosettes are also common. Only rarely is melanin pigment or ganglion cells identified.

SPECIAL STAINS/ IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
SPECIAL STAINS
IMMUNOPEROXIDASE	Immunohistochemistry reveals S100 staining around nests of cells and rare positive cells within the nests.
hASH1
*Human achaete-scute* Homologue (hASH1) mRNA Level as a Diagnostic Marker to Distinguish Esthesioneuroblastoma From Poorly Differentiated Tumors Arising in the Sinonasal Tract Paulette Mhawech, MD, Margaret Berczy, MT, etal.**	Am J Clin Pathol 2004;122:100-105 Abstract quote Distinction of high-grade esthesioneuroblastomas from other poorly differentiated tumors arising in the nasal cavity is an important diagnostic challenge because it determines patient management and prognosis. The human achaete-scute homologue (hASH1) gene is critical in olfactory neuronal differentiation and is expressed in immature olfactory cells; therefore, it could have potential use as a diagnostic marker. The aim of the present study was to determine the value of hASH1 messenger RNA (mRNA) levels in differentiating esthesioneuroblastoma from other poorly differentiated tumors. A real-time polymerase chain reaction assay was developed, permitting the comparative determination of hASH1 mRNA levels in triplicate in a double-blind pilot study including 24 frozen cases of esthesioneuro-blastoma and poorly differentiated tumors. All 4 positive cases were esthesioneuroblastomas, and all 19 poorly differentiated tumors were negative. In addition, there was an inverse association between the grade of esthesioneuroblastomas and hASH1 mRNA levels. The hASH1 mRNA level might represent a useful tool for distinguishing esthesioneuroblastoma from poorly differentiated tumors of the sinonasal region.

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
Sinonasal undifferentiated carcinoma	No Homer-Wright rosettes or neurofibrillary stroma Considerable nuclear pleomorphism, prominent mitoses, and vascular invasion Keratin and EMA positive Synaptophysin negative

PROGNOSIS	CHARACTERIZATION
METASTASTIC DISEASE
Local Disease	68%
Nodal Involvement	22%
Distant Spread	16%

Kadish Staging System

Stage	Location	5 Year Survival
A	Disease confined to the nasal cavity	75%
B	Disease confined to the nasal cavity and paranasal sinuses	68%
C	Local or distant spread beyond the nasal cavity or sinuses	41%

TREATMENT

CHARACTERIZATION

GENERAL

Complete surgical excision which may be supplemented with chemotherapy and radiation is the treatment.

Unfortunately, these tumors may recur even after a decade or more. The cervical lymph nodes are the most common site of metastases followed by the lungs, abdominal organs, long bones, and pelvis.

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Pathogenesis
Histopathological Features and Variants
Special Stains/ Immunohistochemistry/ Electron Microscopy
Differential Diagnosis
Prognosis
Treatment
Commonly Used Terms
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