Mast cell sarcoma: 2 Mayo Clinic cases

Granularity in disease classification impacts survival prediction in advanced systemic mastocytosis: A single institution study of 329 informative cases

“…SM remains an enigmatic disease that appears to be driven by KIT mutation but with markedly heterogeneous clinical and morphological presentation 10 . At one extreme are ICC‐defined MCL (i.e., WHO‐defined MCL with immature cytomorphology) 5 and mast cell sarcoma, 11,12 with median survival measured in weeks, while a near‐normal life expectancy is possible with ISM 13 . Both the ICC 1,2 and WHO 3 classification systems start with a broad classification scheme that distinguishes SM‐Adv from ISM or SSM, based primarily on long‐term clinical outcome and presence (SM‐Adv) or absence (ISM/SSM) of at least one “C,” as in “cytoreduction‐requiring,” finding; the latter includes (i) cytopenia (hemoglobin <10 g/dL, absolute neutrophil count <1 × 10 9 /L, or platelet count <100 × 10 9 /L) related to BM MC infiltration, (ii) palpable hepatomegaly with liver function test abnormalities or ascites or portal hypertension, (iii) palpable splenomegaly with thrombocytopenia, (iv) malabsorption with weight loss secondary to MC infiltration of the gastrointestinal system, and (v) large osteolytic lesions with or without pathological fractures 1,2 .…”

“…ICC, International Consensus Classification; MCL, mast cell leukemia; SM-AHN, systemic mastocytosis with associated hematologic neoplasm; SM-ALN, SM with associated lymphoid neoplasm; SM-AMN, SM with associated myeloid neoplasm; SM-AMN/MPN, SM with associated myeloproliferative neoplasm; SM-AMN/not MPN, SM with associated myeloid neoplasm other than MPN; WHO, World Health Organization. [Color figure can be viewed at wileyonlinelibrary.com]study,11 median survival was 198 months in ISM, 41 months in ASM, 24 months in WHO-defined SM-AHN, and 2 months in ICC-defined MCL. In the current study, we recruited the study population of SM-…”

Diagnostic and therapeutic challenges in mast cell sarcoma

“…The highly atypical morphological appearance of neoplastic cells often presents a risk of misdiagnosis, due to the similarity with carcinoma metastases, anaplastic lymphomas, or histiocytic neoplasms 5 . The sparse literature shows a dramatic prognosis, also due to the rapid evolution to mast cell leukemia (MCL) 6,7 …”

“…5 The sparse literature shows a dramatic prognosis, also due to the rapid evolution to mast cell leukemia (MCL). 6,7 In addition to the classical MCS variant, MCS-like progression of SM can be observed, with persistence of the mutant KIT as the driver of the disease (more rarely observed in de novo MCS) and molecular mechanisms of evolution yet to be elucidated. 8 Due to severe pain, the patient received radiotherapy (DTF 44/44 Gy, fractioning 2 Gy/d for 5 days per week), experiencing transient amelioration of symptoms.…”

Reappraisal of mast cell leukemia based on a single institution review of 16 cases: Mast cell morphology determines clinical outcome

“…subtyped into five variants, based partly on the presence or absence of B (MC burden) and C (MC-associated organopathy) findings: indolent (ISM), smoldering (SSM), aggressive (ASM), SM with an associated myeloid neoplasm (SM-AMN), and mast cell leukemia (MCL) 2 ; mast cell sarcoma is an extremely rare and deadly type of mast cell malignancy that is distinguished from MCL. 4 To render a diagnosis of MCL, the revised 4th edition of the World Health Organization (WHO) classification system required the presence of ≥20% MCs in BM aspirate smear and mentions their usual morphology as being immature and atypical and as being round rather than spindle-shaped. 5 The revised WHO classification also considered both leukemic (circulating MC ≥10%) and aleukemic variants of MCL.…”