ICD-O-1 Morphology

Effective 1978 - 1991

ICD-O-2 Morphology

Effective 1992 - 2000

ICD-O-3 Morphology

Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

C421
Primary site must be bone marrow (C421)

Grade

Not Applicable

Module Rule

None

Alternate Names

MCL

Definition

Mast cell leukemia is the leukemic variant of systemic mastocytosis (9741/3) in which bone marrow aspirate smears contain greater than or equal to 20% mast cells. These mast cells are usually immature and atypical and are often round rather than spindle-shaped.

In classic mast cell leukemia, mast cells account for greater than or equal to 10% of the peripheral white blood cells.

In most patients, skin lesions are detectable. Bone marrow biopsy shows a diffuse, dense infiltration with atypical, immature mast cells. Organ damage is usually present at diagnosis.

General criteria for systemic mastocytosis have been established and there are 5 variants. Each variant has specific criteria, below are the criteria for mast cell leukemia.

1. Meets the general criteria for systemic mastocytosis.
2. Bone marrow biopsy shows diffuse infiltration (usually dense) by atypical, immature mast cells.
3. In classic cases, mast cells account for greater than or equal to 10 percent of the peripheral blood white blood cells, but the aleukemic variant (in which mast cells account for less than 10%) is more common.
4. Skin lesions are usually absent

Abstractor Notes

If the leukemia occurs before or simultaneously with Mast Cell Sarcoma (9740/3), see M3 and Module 5:PH 9.

Definitive Diagnostic Methods

Bone marrow biopsy
Genetic testing

Genetics Data

CBL
KIT D816V
non-D816V codon 816 mutations
non-codon 816 mutations
TET2
SRSF2

Immunophenotyping

None

Treatments

Chemotherapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Corresponding ICD-9 Codes

207.8 Other specified leukemia

Corresponding ICD-10 Codes

C94.3 Mast cell leukemia

Corresponding ICD-10-CM Codes (U.S. only)

C94.3 Mast cell leukemia (effective October 01, 2015)

Signs and Symptoms

Abdominal pain
Bleeding (hemorrhage)
Bone pain
Dermatographism
Diaphoresis
Flushing
Gastrointestinal distress
Headache
Osteopenia/osteoporosis
Respiratory problems
Weight loss

Progression and Transformation

None

Epidemiology and Mortality

Survival: ~ few months

Sources

Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Mastocytosis
Pages: 69

International Classification of Diseases for Oncology, Third Edition, First Revision. Geneva: World Health Organization, 2013.
Section: ICD-O-3.1 (2011) Morphological Codes
Pages: http://codes.iarc.fr/codegroup/2
Glossary