Clinical features
These tumours arise across a broad age range. Tumour arise in the nasal mucosa of the upper nasal cavity.
Histopathology
Tumours small to medium size cells with pale eosinophilic cytoplasm. Nuclei are round with fine chromatin and without conspicuous nucleoli. The cells form well-defined nests of cells embedded in a fibrous stroma. There may be a prominent capillary network. The tumour cells form rosettes, at least focally. There may be foci of squamous or glandular differentiation Rarely, there is maturation to ganglioneuroblastoma.
Immunohistochemistry
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positive |
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variable: positive in spindle cells at periphery of nests |
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20-25% of cases1, mainly in foci of squamous or glandular differentiation |
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variable |
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variable |
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variable |
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variable |
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variable |
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negative |
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negative |
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negative |
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negative |
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negative |
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negative |
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Ultrastructure
There are numerous neuroendocrine granules and neural cell processes.
Differential diagnosis
sinonasal small cell neuroendocrine carcinoma; there is a high mitotic rate and necrosis is prominent. Neurofibrillary stroma an S-100 positive cells are lacking. There may be diffuse cytokeratin positivity.
alveolar rhabdomyosarcoma: negative for neuroendocrine markers and S-100 but positive for desmin and actin.
melanoma, small cell variant: show more pleomorphism and are negative for neuroendocrine markers but diffusely positive for S-100.
teratocarcinosaroma
pituitary adenoma: express cytokeratins and specific pituitary hormones.
Prognosis
Depends on the clinical stage but is often unpredictable. Longer disease-free survival is associated with:
increased number of S-100 positive cells.
a Ki-67 proliferation index below 10%
References
Diagnostic histopathology of tumors. Edited by CDM Fletcher. 2nd edition. Churchill Livingstone. Page 113.
1Perez-Ordonex B. Special tumours of the head and neck. Current Diagnostic Pathology 2003;9:366-383.
This page last revised 16.2.2004.
©SMUHT/PW Bishop