P-1563. Unraveling a good paradox - Tertiary center experience with Good syndrome and its infectious complications; Insights from 32 cases identified through 2024

Abstract Background Good syndrome (GS) is an under-recognized adult-onset immunodeficiency characterized by the coexistence of thymoma and hypogammaglobulinemia. It is marked by recurrent infections, combined B- and T-cell immunodeficiency, and frequent autoimmune manifestations. Its rarity, unclear pathogenesis, and often delayed diagnosis contribute to its clinical complexity.Distribution of Infections by pathogen type in patients with Good Syndrome: the microbiological spectrumDemographics, clinical characteristics, thymoma classification with staging and management Methods We conducted a retrospective review of adults diagnosed with good syndrome at Mayo Clinic up until 2024. We assessed baseline characteristics, clinical features with a particular focus on infectious complications, immunological lab parameters, thymoma histopathology with staging, and management. Descriptive statistics were utilized for analysis.Immunological lab parameters and management of Good syndrome Results During the study period, Good syndrome was diagnosed in 32 patients; 78% were male, with a median age at diagnosis of 62 years (Table 1). All patients had thymoma, the majority of which were stage I (localized), and most underwent thymectomy as part of management. The median delay in GS diagnosis following thymoma diagnosis was 1,486 days (interquartile range IQR: 406.75–1,992.75). Infectious complications were observed in 30 of 32 patients (97%), most commonly sinopulmonary infections (87%) (Figure 1). Bacterial infections were documented in 29 patients (94%), viral in 14 (45%), fungal in 13 (42%), and mycobacterial in 3 (10%) (Figure 2). Immunologic data were available for 22 patients. Reduced CD4+ T-cell counts and severe B-cell lymphopenia were observed in 77%. IgM and IgG deficiencies were the most prevalent, present in 82% of cases. Most patients received monthly immunoglobulin replacement; additionally, 59% were prescribed oral antimicrobial prophylaxis due to their elevated risk of infections. All-cause mortality was 31% (n=10); among these, 3 deaths (10%) were directly attributable to complications of Good syndrome. Conclusion We observed a significant delay (Median of 4.07 years) in the diagnosis of Good syndrome following thymoma detection. Given the high risk of infectious complications and associated mortality, clinicians should maintain a high index of suspicion and consider early immunologic evaluation in adults with recurrent or opportunistic infections, particularly in the context of a known thymoma. Disclosures All Authors: No reported disclosures