NCI Definition: An indolent mast cell neoplasm characterized by systemic infiltration of skin and internal organs by aggregates of neoplastic mast cells. There is no evidence of mast cell leukemia or clonal hematologic malignancy. Clinically, there is no evidence of palpable hepatomegaly and splenomegaly, malabsorption syndrome, or pathologic fractures. [1]

Indolent systemic mastocytosiss most frequently harbor alterations in NPM1 and IDH2 [2].

Most Commonly Altered Genes in Indolent Systemic Mastocytosis

NPM1fs, IDH2 R140Q, IDH2 Mutation, IDH2 Exon 4 Mutation, and IDH2 Codon 140 Missense are the most common alterations in indolent systemic mastocytosis [2].

Top Alterations in Indolent Systemic Mastocytosis

Disease Details

Systemic Mastocytosis
OncoTree Name
Indolent Systemic Mastocytosis
OncoTree Code


1. National Cancer Institute. NCI Thesaurus Version 18.11d. https://ncit.nci.nih.gov/ncitbrowser/ [2018-08-28]. [2018-09-21].

2. The AACR Project GENIE Consortium. AACR Project GENIE: powering precision medicine through an international consortium. Cancer Discovery. 2017;7(8):818-831. Dataset Version 8. This dataset does not represent the totality of the genetic landscape; see paper for more information.

3. All assertions and clinical trial landscape data are curated from primary sources. You can read more about the curation process here.