Pure Red Cell Aplasia Associated With Thymoma: A Case Report

A 55-year-old male, former smoker, presented with exertional dyspnea associated with an anterior mediastinal mass. Biopsy findings were consistent with a type B2 thymoma. The tumor was deemed unresectable, and curative concurrent chemoradiotherapy was not feasible after three cycles of cyclophosphamide, adriamycin (doxorubicin), and platinum (cisplatin) (CAP) chemotherapy. Treatment was therefore continued to six cycles. Following radiological progression, second-line chemotherapy with paclitaxel and carboplatin was initiated. After two cycles, the patient developed superior vena cava syndrome. Palliative mediastinal radiotherapy was subsequently delivered. The patient experienced five episodes of severe hyporegenerative anemia, in the absence of bleeding or hemolysis, requiring repeated blood transfusions. Both the bone marrow aspirate and the bone marrow biopsy revealed pure red cell aplasia (PRCA). Testing for parvovirus B19 infection was negative. Immunosuppressive therapy with prednisone, combined with third-line etoposide-based chemotherapy, was initiated. However, the patient discontinued treatment after two cycles and remained transfusion-dependent during follow-up. This case highlights the diagnostic and therapeutic challenges posed by thymoma-associated PRCA in patients with advanced unresectable disease.