Abstract
Mast Cell Leukemia (MCL), a rare subtype of systemic mastocytosis is defined by bone marrow involvement as atypical and aleukemic mast cells, if more than 20% and less than 10% of peripheral WBCs are mast cells, respectively. We met a case of aleukemic MCL presenting with anemia and ascites for 2 years, referred for BM evaluation, suspicious of leukemia. Our findings included BM involvement by diffused aggregates of oval- and spindle-shaped atypical mast cells, lacking mature mast cells and other hematopoietic cells. The mast cells were absent in peripheral blood smear. Further assessments showed positive reaction of mast cells metachromatic granules with Tryptase, Giemsa and Toluidine blue stains, the expression of CD117/KIT and CD45 by immunohistochemistery, and elevated level of serum Tryptase. Radiologic investigations revealed generalized lymphadenopathy, and massive hepatosplenomegaly, followed by the cervical lymphadenectomy, and liver wedge biopsy. Suspicious peritoneal lesions were identified and underwent excisional biopsy. Microscopic evaluations showed lymph nodes and liver involvement by cancer cells and the same features in peritoneal seeding. Multiple organs damage progressed in few months and the patient died despite surgery and chemotherapy. In conclusion, we report an extremely rare case of aleukemic MCL with multiple organs damage such as liver, peritoneum, spleen, gastrointestinal tract and BM, presenting by ascites. According to this case and previous parallel studies, we suggest some clinicopathologic features in favor of poor prognosis, including the presence of multiple organs damage, hepatomegaly, ascites, peritoneal seeding, the absence of mature mast cells and other hematopoietic cells in the BM, and elevated serum Tryptase level.