Systemic Mastocytosis in Association with Small Lymphocytic Lymphoma

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Systemic mastocytosis (SM) is a rare disorder, predominantly associated with myeloid neoplasms.
• Lymphoproliferative disorders are infrequently linked to SM, with few documented cases of SM with chronic lymphocytic leukemia.
• This report details a rare instance of indolent SM coexisting with small lymphocytic lymphoma (SLL).

Observation:

• Bone marrow biopsy revealed mast cell clusters and perivascular infiltration, positive for tryptase, CD2, and CD25.
• Small lymphocytic lymphoma (SLL) involvement was noted in 30% of the bone marrow, presenting as interstitial lymphoid aggregates.
• Flow cytometry confirmed B-cells expressing CD19, CD20, CD5, CD23, and kappa light chains, with CD38 expression below 5%.

Findings:

• The co-occurrence of systemic mastocytosis and small lymphocytic lymphoma is exceptionally rare.
• Diagnostic markers for both mastocytosis (tryptase, CD2, CD25) and SLL (CD19, CD20, CD5, CD23) were identified.
• The patient presented with indolent SM and low-risk SLL.

Implications:

• Management strategies for combined SM and SLL focus on treating each entity independently.
• Clinical surveillance is crucial for monitoring disease progression in indolent SM and low-risk SLL.
• Understanding rare hematologic co-morbidities like SM with SLL is vital for comprehensive patient care.