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SEER Inquiry System - Report
Produced: 02/28/2026 1:42 PM
Question 20100028
Inquiry Details
References:
#1: ICD-O-3
#2: WHO Class H & N Tumors, 66, 69. 2005
Question:
Primary site/Histology--Head & Neck: How are these fields coded when the final diagnosis for a skull based mass is "neuroendocrine carcinoma" and the IHC studies are incompatible with a brain/spinal cord primary (ependymoma)? See Discussion.
Discussion:
The pathology report final diagnosis is, "skull base mass, biopsy: neuroendocrine carcinoma, see note. NOTE: Ancillary IHC studies reveal ...the IHC signature is incompatible with ependymoma. The constellation of findings is diagnostic of well differentiated neuroendocrine carcinoma."
The site/histology combination of C410 and 8246/3 is 'impossible' by SEER edits. There is no override. What is the correct primary site and histology?
Answer:
According to our subject matter expert physician, this unusual case is most likely a sino-nasal tumor (some variant of esthesioneuroblastoma [olfactory neuroblastoma]). Code to nasal cavity [C300] as indicated in ICD-O-3 by site-associated topography code attached to the morphology code for olfactory neuroblastoma [9522/3].
