Systemic mastocytosis: bone marrow pathology, classification, and current therapies

Area of Science:

• Hematology
• Oncology

Background:

• Mast cell disease (MCD) is defined by neoplastic mast cell (MC) proliferation in organs.
• Diagnosis often relies on bone marrow (BM) histology and immunohistochemistry.
• Challenging diagnoses may require special stains like tryptase and CD25.

Purpose of the Study:

• To review the diagnosis, classification, and treatment of mast cell disease.
• To highlight diagnostic challenges and therapeutic strategies for MCD.
• To discuss the role of specific genetic mutations in treatment response.

Main Methods:

• Histological and immunohistochemical examination of bone marrow trephine specimens.
• Application of special stains (tryptase, CD25) for diagnosis.
• Review of updated classification criteria for MCD.
• Analysis of treatment outcomes based on genetic mutations (FIP1L1-PDGFRA, c-kit D816V).

Main Results:

• Diagnosis can be straightforward or challenging based on MC infiltration patterns and associated neoplasms.
• An updated classification aids in categorizing MCD patients.
• Some cases overlap with other myeloid neoplasms, complicating classification.
• Imatinib mesylate shows efficacy in FIP1L1-PDGFRA-positive MCD patients, unlike those with c-kit D816V mutations.

Conclusions:

• Mast cell disease diagnosis requires careful evaluation of BM pathology and classification criteria.
• Treatment for MCD is patient-specific, with cytoreductive therapies for progressive disease.
• Targeted therapy with imatinib mesylate is effective for a subset of MCD patients with specific oncogenic mutations.