A rare case of systemic mastocytosis with t(8;21) acute myeloid leukaemia in a young girl: a case report

Mastocytosis is a rare disorder due to the abnormal proliferation of clonal mast cells. Mast cells exist in most tissues, mature in situ from hematopoietic stem cells and develop unique characteristics of local effector cells. It manifests as two main categories: cutaneous mastocytosis and systemic mastocytosis (SM). Patients presenting with SM–acute myeloid leukaemia (AML) often have the worst outcome. Here we present a patient with the simultaneous diagnosis of SM associated with t (8;21) (q22;q22) acute myeloid leukaemia, M2 subtype in the French-American-British (FAB) classification, carrying a population of immature mast cell precursors. Initially, she was diagnosed with AML with t (8;21) (q22;q22) and was started on induction chemotherapy. Subsequent trephine biopsy evaluation post-induction chemotherapy showed no increase in blast cells. However, abnormal mast cells were seen distributed throughout the marrow spaces, which expressed mast cell tryptase, CD117 and CD68. She was then diagnosed as SM associated with t(8;21) (q22;q22) AML. Unfortunately, she succumbed to death due to severe neutropenic sepsis post- induction chemotherapy. By sharing the knowledge, hopefully it will help the clinicians as the diagnosis of SM is difficult to establish because the associated malignancy may obscure the morphological features of SM. However, a reduction in blast cell percentage at the time of a post-induction marrow evaluation helps in diagnosis. Bangladesh Journal of Medical Science Vol. 23 No. 03 July’24 Page : 873-876