Beyond the Usual Suspects: Unraveling Spleen Mastocytosis in Hypersplenism Differential Diagnosis.

Systemic mastocytosis (SM) poses a diagnostic challenge. This hematologic disorder involves abnormal mast cell proliferation and concurrent tissue infiltration. SM clinical presentation is not uniform, with patients displaying a wide array of symptoms related to different organ infiltration and mast cell mediators. Splenomegaly, while not typical or specific to SM, might be present from an early stage to advanced stage, especially in the presence of thrombocytopenia. Early detection is crucial for optimal patient outcomes. We present an atypical case of SM with spleen involvement in a 63-year-old male patient with a history of persistent thrombocytopenia for five years. Upon splenectomy, histological findings were compatible with infiltration with mast cells. Remarkably, the patient showed improvement and did not require additional cytoreductive therapy. This case underlines the importance of recognizing this rare presentation and highlights the potential therapeutic role of splenectomy in aggressive SM.