Abstract
Bone marrow mastocytosis may be associated with many clonal non mast cell hematological neoplasms and its association with acute myeloid leukemia especially with t (8; 21) has been described. We describe an interesting case of coexistence of systemic mastocytosis with acute myelomonocytic leukemia in a young child. Diagnosis of acute myelomonocytic leukemia was based on bone marrow aspirate findings coupled with cytochemistry. Systemic mastocytosis was diagnosed on the basis of bone marrow biopsy findings showing blasts as well as multifocal dense mast cell infiltrates with spindling and atypical morphology which was confirmed on toluidine blue staining.