Massive splenomegaly requiring differential diagnosis of hematologic malignancies

An 85‐year‐old woman presented with pain and a palpable mass in her left flank. Abdominal computed tomography revealed massive splenomegaly and para‐aortic lymphadenopathies. Bone marrow biopsy showed CD79a, CD20, and bcl‐2‐positive atypical lymphocytes, which led to the diagnosis of splenic marginal zone lymphoma. The causes of massive splenomegaly are hematologic diseases, malignancies, infection, and infiltrative conditions. When seeing massive splenomegaly, hematologic diseases, especially malignant diseases, should be ruled out first.