[Good's syndrome developing hemophagocytic lymphohistiocytosis following thymectomy]

This report presents the case of a 68-year-old female patient previously diagnosed with thymoma by her local doctor. She was referred to our hospital for surgery, and the thymoma was removed and diagnosed as a World Health Organization (WHO) classification type AB thymoma. After surgery, she experienced general malaise, a loss of appetite, and weight loss, so she visited our hospital in May 2019. A blood test showed hypogammaglobulinemia and low B lymphocytes. A bone marrow examination revealed no morphological abnormalities. Flow cytometric analysis indicated a marked decrease in both the B cell-related surface markers CD19 and CD20 and the T cell-related surface marker CD4, and the CD4/CD8 ratio was also low. She was diagnosed with Good's syndrome, and immunoglobulin replacement therapy was administered. She subsequently developed hemophagocytic lymphohistiocytosis (HLH) due to infection and was treated according to the HLH2004 protocol, but she finally succumbed to multiple organ damage as a result of sepsis. Given that Good's syndrome is associated with both humoral and cellular immune dysfunctions, affected patients tend to develop severe infections and have a poor prognosis. In such cases, early detection, regular immunoglobulin replacement therapy, and infection prevention therapies are important.