Good's syndrome (GS) is a primary immunodeficiency characterized by thymoma and humoral immunodeficiency. It is the most unusual form of the parathymic syndrome, after far behind myasthenia gravis or pure red cell aplasia.1 The most common forms of clinical presentation are recurrent infections, hematological changes, and chronic diarrhea.1,2

We report the case of a 76-year-old man with a history of arterial hypertension, a former smoker of 20 pack-years, with chronic diarrhea which yielded Campylobacter coli on culture. He was referred to the respiratory medicine department for repeated respiratory infections. Forced spirometry showed mild obstruction: FEV1/FVC 0.67, FEV1 2.1 l (87%), FVC 3.17 l (98%). Skin prick tests for airborne allergens were negative. Clinical laboratory tests showed hemoglobin 11.7g/dl with normal corpuscular volume, with no impact on platelet levels, and markedly reduced CD19 lymphocytes, with a CD4/CD8 ratio of 1.04. Immunoglobulin levels were low: IgA <5mg/dl, IgG <74mg/dl, IgM <5.3mg/dl. Methicillin-resistant Staphylococcus aureus was isolated from repeated sputum cultures. Computed tomography (CT) of the paranasal sinuses showed occupation of the maxillary sinuses, while the chest CT revealed mild bronchiectasis in the middle lobe, lingula and both lower lobes, and a solid multilobulated mass in the anterior mediastinum suggestive of thymoma. VATS was performed, confirming the histological diagnosis of polygonal cell cortical thymoma. With these findings, the patient was determined to have GS, and immunoglobulin replacement therapy was started. He showed good progress and the number of infections fell.

GS mostly appears in patients in their 30s or 40s (unlike our patient), and affects men and women equally.1 This immunodeficiency is caused by an antibody deficit, and is currently classified as a different entity to common variable immunodeficiency (CVID).1 It accounts for 2% of cases of primary antibody deficiency treated with immunoglobulin replacement therapy.3

The most common clinical manifestation is recurrent respiratory infection, and the major pathogens are Haemophilus influenzae and Pseudomonas spp. The chronic diarrhea presented by 50% of patients appears to have an autoimmune basis, and the isolation of pathogenic agents is anecdotal.3

Diagnosis is based on the clinical picture and immune response studies. The latter are characterized by reduced B cells and hypogammaglobulinemia with reduced CD4 T cells and an inversed CD4/CD8 ratio.1

Treatment of choice is regular intravenous administration of gammaglobulins to treat the humoral immunity, providing clinical benefit in most cases.2 Resection of the thymoma is also indicated, to prevent the potential risk of locally invasive growth and metastatic dissemination, although the procedure does not seem to improve immunodeficiency.2