Systemic mastocytosis

Name
Systemic mastocytosis
ICD-O-1 Morphology
9741/3
Effective 1978 - 1991
ICD-O-2 Morphology
9741/3
Effective 1992 - 2000
ICD-O-3 Morphology
9741/3
Effective 2001 and later
Reportable
for cases diagnosed 1978 and later
Primary Site(s)
C421

Help me code for diagnosis year :

Grade
9 - Grade/differentiation unknown, not stated, or not applicable
Module Rule
None
Alternate Names
Aggressive systemic mastocytosis
ASM
Lymphadenopathic (systemic) mastocytosis with eosinophilia
Malignant mastocytosis
SM
SM-AHNMD
Systemic mastocytosis with associated clonal hematological non-mast cell lineage disease
Systemic tissue mast cell disease
Definition
Accumulation of increased numbers of mast cells in the tissues other than skin, such as the liver, spleen, bone marrow, stomach, and small intestines, with or without skin lesions. There are > 15% mast cells in aggregates in the bone marrow and/or other extracutaneous organs. The aggregates of neoplastic spindle-shaped mast cells are compact (not scattered throughout tissue).
Abstractor Notes
Bone marrow is almost always involved. Lymph nodes are rarely involved except for a variant of aggressive of systemic mastocytosis. The white and red pulp of the spleen may be involved. Involvement of liver may present with small granulomatoid foci of mast cells, but severe liver involvement is rare. It may frequently be suspected that the GI tract mucosa is involved based on symptoms, but it is rarely assessed morphologically. Blood abnormalities include anemia, leukocytosis, eosinophilia, neutropenia and thrombocytopenia.

There are several variants of SM reportable as 9741/3 described below. [Indolent systemic mastocytosis (ISM) is NOT reportable; it includes subtypes bone marrow mastocytosis and smoldering systemic mastocytosis and would be coded as 9741/1 in the WHO classification; the mast cell burden is very low (<1% of nucleated bone marrow cells) and life expectancy is normal.]

Aggressive systemic mastocytosis (ASM): Organomegaly and impaired organ function are usually present. There may be weight loss caused by malabsorption in the GI tract due to mast cell infiltrates, or skeletal involvement with large osteolytic lesions and/or pathologic fractures. There are usually no skin lesions. A type of ASM, lymphadenopathic mastocytosis with eosinophilia, features progressive lymphadenopathy with peripheral blood eosinophilia, often with extensive bone involvement and hepatosplenomegaly. Genetically cases classified as ASM have no PDGFRA rearrangement. Survival is a few years.

In systemic mastocytosis with associated clonal hematological non-mast-cell lineage disease (SM-AHNMD), a myeloid or lymphatic malignancy is diagnosed with the SM; CMML (9945/3) is the most common associated disease. The prognosis is usually dominated by the non-mast cell malignancy.

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Definitive Diagnostic Methods
Bone marrow biopsy
Histologic confirmation
Genetics Data
For ASM: no FDGFRA rearrangement
Somatic point mutation at codon 816 in kit receptor gene
Immunophenotyping
CD2+
CD25+
CD117+
Immunohistochemical markers anti-tryptase/chymase and anti-CD117
Treatments
Blood thinners; anti-coagulant medications
Chemotherapy
Immunotherapy
Other therapy
Transformations to
No Transformations
Transformations from
No Transformations
Corresponding ICD-9 Codes
202.6 Malignant mast cell tumors
Corresponding ICD-10 Codes
C96.2 Malignant mast cell tumor
Corresponding ICD-10-CM Codes (effective October 1, 2015 U.S. only)
C96.2 Malignant mast cell tumor
Signs and Symptoms
None
Diagnostic Exams
None
Recurrence and Metastases
None
Epidemiology and Mortality
None