Does Thymoma Plus Hypogammaglobulinemia Define Good Syndrome? A 30-Year Longitudinal Study of a Single Patient with Persistent B-Cell Preservation

Good syndrome is commonly diagnosed when thymoma and hypogammaglobulinemia coexist, although universally accepted diagnostic criteria are lacking. Profound B-cell lymphopenia is one of its most consistent immunological features. We describe a woman followed for 30 years in our unit whose severe antibody deficiency preceded thymoma detection by 14 years. Circulating B cells were preserved before thymectomy and throughout 16 years of subsequent follow-up, with maintained class-switched memory B cells despite persistent antibody deficiency. Her clinical course was favorable under immunoglobulin replacement, without documented major opportunistic infections. T-cell differentiation abnormalities were present despite preserved absolute counts. These findings suggest that patients currently classified as Good syndrome may represent a more heterogeneous group than traditionally assumed. Although preserved B cells do not exclude Good syndrome under existing definitions, the present observation should be considered hypothesis-generating and supports further studies evaluating potential biological heterogeneity among patients diagnosed with Good syndrome. This case highlights the need for consensus diagnostic criteria that consider the temporal relationship between both conditions, B-cell numbers, and the accompanying immune abnormalities, rather than relying on the coexistence of thymoma and hypogammaglobulinemia alone.