A case report of Good syndrome: Diarrhea and dyspnea

RATIONALE: Good syndrome (GS) is a rare acquired immunodeficiency disorder characterized by thymoma, hypogammaglobulinemia, and peripheral B-cell lymphopenia. Because of its rarity and complexity, the diagnosis and treatment of this condition remain inadequately reported in clinical practice. Therefore, we report a typical case of GS in a patient who developed chronic diarrhea and recurrent pneumonia several years after thymectomy, with the aim of improving the understanding and early recognition of this disease. PATIENT CONCERNS: A 55-year-old Chinese woman presented with chronic diarrhea and recurrent severe pneumonia, which developed 3 and 6 years, respectively, after thymectomy for a mixed-type (B2/B3) thymoma. DIAGNOSES: Laboratory examination results revealed severe hypogammaglobulinemia (immunoglobulin G = 3.9 g/L), peripheral blood B-cell lymphopenia (B lymphocytes 12 cells/μL), and cellular immune dysfunction (CD4+/CD8+ ratio 0.31, CD(16 + 56): 0.23%, CD19: 3.31%). The diagnosis was confirmed based on the combination of clinical manifestations, laboratory findings, and imaging examinations. GS was diagnosed based on the triad of thymoma history, humoral and cellular immunodeficiency, and recurrent opportunistic infections. INTERVENTIONS: The patient received long-term intravenous immunoglobulin (IVIG) replacement therapy, prophylactic antibiotics, and aggressive management of acute infections. OUTCOMES: Despite regular IVIG therapy, the patient's condition progressively deteriorated over 8 years, and the patient ultimately died at home, likely due to respiratory failure secondary to severe pulmonary infection (the family declined an autopsy). LESSONS: This case highlights that GS can manifest several years after thymectomy, necessitating sustained clinical vigilance. This case also highlights the limitations of conventional IVIG therapy and underscores the need to enhance clinicians' awareness of GS.