Thymoma-associated aplastic anemia initially presenting as bicytopenia: a case report and therapeutic challenges

Abstract Aplastic anemia (AA) is a condition characterized by bone marrow failure caused by an immune-mediated response involving cytotoxic T cells. While the etiology of AA is often idiopathic, it can also result from factors such as drugs, toxins and immunologic diseases. Thymomas, tumors located in the anterior mediastinal, are associated with various autoimmune conditions including AA. In this report, we present a case of severe aplastic anemia associated with thymoma, highlighting its clinical presentation, laboratory findings, and histopathologic features. A 54-year-old Thai woman with a history of dyslipidemia presented with a 1-month history of chronic progressive dyspnea and significant weight loss. On examination, she had physical signs of anemia, petechiae, and a left lung mass. Laboratory tests revealed anemia with reticulocytopenia, thrombocytopenia and a normal total white blood cell count with a reversed neutrophil-to-lymphocyte ratio (absolute neutrophil count 1.4 x 109/L). Bone marrow studies demonstrated hypocellularity with absent megakaryocytes. A computed tomography scan identified a 12.7 cm anterior mediastinal mass, and a biopsy confirmed type AB thymoma. She received a diagnosis of thymoma-associated AA. Despite treatment with cyclosporine, eltrombopag, blood transfusions, and thymectomy, the patient succumbed to a severe infection 4 months after diagnosis.