Background: Mastocytosis is an abnormal proliferation of mast cells and their subsequent accumulation in various organs. Diagnosis of mast cell disease relies on proper identification of abnormal mast cells.
Case: A 55-year-old man presented with a history of fever for several months, associated with night sweats, involuntary 20lb weight loss, progressive fatigue, weakness, worsening abdominal distention, shortness of breath, and diffuse lymphadenopathy.