Case Number : Case 2812- 16 April 2021 Posted By: Dr. Richard Carr

?Olfactory Neuroblastoma. 

rosette like structures are seen. But not much necrosis

go with olfactory neuroblastoma

This isn't very dermatological!

Olfactory Neuroblastoma

pigmentary Olfactory neuroblastoma

I was asked to review the case with the question can this be metastatic melanoma (hence the "dermatopathological" opinion from a colleague. The pan-keratin appeared negative, the S100 negative and the melanA looks funny but possible positive. I expanded the panel to include Sox10, HMB45 - negative and BerEP4 which was diffusely positive. Could not see rosettes actually they seem to be epithelial structures and very close scrutiny there was very focal dot-like positive staining for Cam5.2 and Pan-keratins. So final diagnosis awaits review by the ENT / neuro team at a local major centre but I concluded as follows: DDx Neuroendocrine carcinoma, olfactory neuroblastoma, NUT midline carcinoma, PNET. So far not managed to see the tumour from the eye (we could not yet trace the histopathology).

Interesting case, important to think of non-dermatopathological differentials during skin consults!

I've now seen the opinion of the specialist ENT pathologist as follows:

Further calcitonin, prolactin, pit-1, p63 protein, Merkel cell marker, HMB45, desmin, CD99, NUT-1, TBX19, SN5 and NR5a studies are negative. Repeat melan A is also paradoxically negative. 
Overall, therefore, these appearances are most in keeping with part of an invasive, poorly differentiated non-small cell (large cell) neuroendocrine carcinoma. In the absence of any alternative origin these appearances are in keeping with a primary sino-nasal derivation. The possibility of a second, irradiation-induced malignancy cannot be excluded. The morphology and immunopheonotype militate against metastatic malignant melanoma, Merkel cell carcinoma, rhabdomyosarcoma, sino-nasal undifferentiated carcinoma (SNUC), undifferentiated carcinoma of nasopharyngeal-type (UCNT; lympho-epithelial carcinoma, small cell undifferentiated neuroendocrine carcinoma (SNUC), myo-pericytic malignancy and lymphoma.