Coombs-Negative Hemolytic Anemia and Thrombocytopenia Associated With Sarcoidosis Confined to the Spleen and Bone Marrow: A Case Report.

Sarcoidosis is a systemic granulomatous disease that typically involves the lungs and lymphatic system. Isolated splenic sarcoidosis with bone marrow involvement is exceedingly rare, and hemolytic anemia associated with sarcoidosis is usually Coombs-positive. We report a case of a 61-year-old man who presented with massive splenomegaly, Coombs-negative hemolytic anemia, and thrombocytopenia. Serum angiotensin-converting enzyme (ACE) and soluble interleukin-2 receptor (sIL-2R) levels were markedly elevated, strongly suggesting malignant lymphoma. Bone marrow biopsy revealed non-caseating granulomas without evidence of malignancy, and 18F-FDG PET/CT demonstrated intense uptake in the spleen with diffuse uptake in the bone marrow. Treatment with prednisolone and a thrombopoietin receptor agonist improved thrombocytopenia, enabling splenectomy. Histopathological examination of the spleen confirmed sarcoidosis. This case highlights the diagnostic challenge of distinguishing sarcoidosis from lymphoma in patients with isolated splenomegaly and markedly elevated sIL-2R levels and demonstrates that sarcoidosis confined to the spleen and bone marrow can present with Coombs-negative hemolytic anemia and thrombocytopenia, with splenectomy playing a crucial role in definitive diagnosis and management.