RESUMEN
Good's syndrome is a rare adult-onset combined immunodeficiency. The association of hypogammaglobulinaemia with a history of recurrent infectious or autoimmune manifestations in a middle-aged patient with evidence of a mediastinal mass should lead to the clinical suspicion of Good's syndrome. The mortality rate associated with infectious complications is high. Thus, although it is rare, the disease should be diagnosed early so that proper treatment can be started. Thymectomy and immunoglobulin replacement are the main therapeutic strategies. We describe the case of a patient with a history of thymoma and recurrent respiratory infections, with a late diagnosis of Good's syndrome in the context of severe organizing pneumonia secondary to COVID-19. LEARNING POINTS: Infection is the leading cause of mortality in patients with Good's syndrome.Early recognition of this rare disease and substitutive therapy with immunoglobulin may have an important impact on prognosis.Due to its rarity, data on Good's syndrome are scarce and its association with severe COVID-19 onset is still unclear.To the best of our knowledge, this is the fifth case report of COVID-19 in a patient with Good's syndrome, the third with a favourable outcome.