ICD-10 Code for Mastocytosis

The ICD-10-CM code for mastocytosis is D47.09 — Other mast cell neoplasms of uncertain behavior. This is the code the Alphabetic Index gives for mastocytosis with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).

Billable

Which mastocytosis code should you use?

The Alphabetic Index lists 6 codes under Mastocytosis. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.

By type

aggressive systemic	C96.21	Aggressive systemic mastocytosis
cutaneous	D47.01	Cutaneous mastocytosis
indolent systemic	D47.02	Systemic mastocytosis
isolated bone marrow	D47.02	Systemic mastocytosis
malignant	C96.29	Other malignant mast cell neoplasm

Mastocytosis cutaneous

congenital	Q82.2	Congenital cutaneous mastocytosis
of neonatal onset	Q82.2	Congenital cutaneous mastocytosis
of newborn onset	Q82.2	Congenital cutaneous mastocytosis

Mastocytosis systemic

with an associated hematological non-mast cell lineage disease

D47.02

Systemic mastocytosis

Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources