MAST CELL LEUKEMIA: A CASE REPORT

Abstract

<h3>Introduction</h3> Systemic mastocytosis (SM) is a rare disorder involving infiltration of clonal mast cells into one or more organ systems, with subsequent episodic mast cell-mediator release and associated inflammatory responses. The most aggressive form of SM is mast cell leukemia (MCL). Diagnosis of MCL requires the presence of >20% atypical mast cells in bone marrow or >10% mast cells in peripheral blood. Prompt recognition and treatment is crucial, as median survival is 2-6 months.^1,2 Here we present a patient with aleukemic MCL. <h3>Case Description</h3> A 65-year-old-male presented with one month of fatigue, anorexia, flushing, diarrhea, and rash to upper extremities. Evaluation revealed pancytopenia, hypogammaglobulinemia, elevated creatinine with proteinuria, elevated alkaline phosphatase. Imaging showed splenomegaly, ascites, and a left humeral lytic focus. Bone marrow biopsy showed 60% blasts/neoplastic mast cells and six percent peripheral blasts; serum tryptase obtained and 1684 ng/ml, with peripheral KIT D816V negative. Pulse dose steroids were initiated. Chemotherapy and midostaurin were discussed with patient, but rapid progression to multi-organ failure occurred, resulting in death 11 days after diagnosis. <h3>Discussion</h3> This patient met multiple criteria considered to be high risk under various SM scoring systems, including age>60, pancytopenia, and elevated alkaline phosphatase and tryptase.^3,4,5,6 Studies on midostaurin indicate post-diagnosis median survival increased to 9-18 months,^7,8 with similar or better survival seen in initial studies of avapritinib.⁹ Early recognition and intervention is key for this most rare form of a rare disorder, and knowing the diagnostic criteria and available treatment options is critical in caring for these patients.