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SEER Inquiry System - Report
Produced: 01/20/2026 3:07 AM
Question 20130013
Inquiry Details
References:
#1: Heme & Lymph Manual & DB
#2: Subject matter expert
Question:
Reportability--Heme & Lymphoid Neoplasms: Is Mast Cell Activation Syndrome (MCAS) reportable?
Discussion:
MCAS has been given an ICD-9 code of 202.60 by our medical record coders. In the Progress Notes, the physicians state this is not the same as systemic mastocytosis. There is no listing for MCAS in the Hematopoietic and Lymphoid Database.
Answer:
Mast Cell Activation Syndrome (MCAS) is not a reportable neoplasm unless it is specifically stated to be a result of a mast cell proliferative disorder that is reportable.
Per our expert pathologist, MCAS is a relatively new term used for conditions in which patients experience the symptoms of mast cell mediators in the absence of an increase/proliferation of mast cells. The diagnosis of this group of disorders is based in part on a complex of symptoms and on the demonstration of no increase in mast cells. Some of these diseases are difficult to separate from mastocytosis (which is reportable). Currently, this group of disorders is not part of the systemic mastocytosis/mast cell leukemia/mast cell sarcoma spectrum.
