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SEER Inquiry System - Report
Produced: 01/21/2026 2:30 AM
Question 20240052
Inquiry Details
References:
#1: WHO Class Hem & Lymph Tumors. 4th edition
#2: WHO Class CNS Tumors. 5th edition
Question:
Reportability/Histology--Heme & Lymphoid Neoplasms: Should a non-Langerhans cell histiocytosis involving the hypothalamus and pituitary gland be accessioned as a reportable, behavior /1, CNS neoplasm? See Discussion.
Discussion:
Imaging identified a mass involving the hypothalamus and pituitary gland and excision of the mass proved “histiocytosis.” The case was extensively reviewed, and the physician notes this patient has a pituitary tumor that is a “non-Langerhans cell histiocytosis,” or a “non-LCH histiocytic neoplasm.”
There is no histology for histiocytosis (NOS) or non-Langerhans cell histiocytosis. However, this does appear to be a non-malignant histiocytic neoplasm. If this were a Langerhans cell histiocytic neoplasm in the CNS it would be reportable. Should this non-Langerhans cell histiocytic neoplasm also be accessioned as a reportable CNS neoplasm? If so, how is the histology coded?
Answer:
Report this case as a pituitary tumor (8000/1) based on the information provided. This is the best choice as no specific histology code exists for this generic term “non-Langerhans cell histiocytosis” in ICD-O-3.2, WHO Classification of CNS Tumors, 5th ed., and WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues, 4th ed.
Be sure to double-check the behavior code of the tumor. Histiocytosis can be benign, borderline, or malignant. There was no mention of the behavior so we defaulted to uncertain behavior for this case.
