Presumed cytomegalovirus retinitis as the initial infectious manifestation of previously unrecognized Good syndrome in an HIV-negative patient: a case report

Background Cytomegalovirus (CMV) retinitis is a sight-threatening opportunistic infection that is uncommon in HIV-negative individuals without identifiable secondary cause of immunosuppression. Good syndrome (GS) is a rare adult-onset immunodeficiency associated with thymoma, and CMV retinitis as its initial infectious presentation is exceptionally rare. Case presentation A 47-year-old HIV-negative woman presented with blurred vision in the right eye for 1 month. She had a history of thymectomy for type AB thymoma and left-eye pars plana vitrectomy (PPV) 2 years earlier. At presentation, best-corrected visual acuity (BCVA) was light perception (LP) in the right eye and no light perception (NLP) in the left eye. Fundus examination revealed extensive hemorrhagic necrotizing retinitis involving the posterior pole and macula. B-scan ultrasonography showed dense vitreous opacities and localized retinal detachment. Optical coherence tomography (OCT) showed retinal thickening, hyperreflective lesions, and disruption of the retinal architecture. The markedly elevated serum CMV DNA level, together with the characteristic fundus findings, supported a clinical diagnosis of presumed CMV retinitis. Intraocular polymerase chain reaction (PCR) confirmation was unavailable because the patient declined aqueous humor sampling. Immunologic evaluation demonstrated absence of peripheral CD19+ B cells, hypogammaglobulinemia, reduced CD4+ T-cell count, and an inverted CD4/CD8 ratio. In the setting of prior thymoma, these findings supported the diagnosis of GS. The patient was treated with intravenous immunoglobulin (IVIG) and intravenous ganciclovir. Serum CMV DNA levels declined substantially after treatment, but visual recovery was limited. Conclusions Presumed CMV retinitis may be the initial infectious manifestation of previously unrecognized GS, with typical combined humoral and cellular immunodeficiency already evident at presentation. In HIV-negative patients with presumed CMV retinitis and no evident secondary immunosuppression, underlying immunodeficiency should be actively investigated. Particular attention should be paid to a history of thymoma, and early systemic immunologic evaluation should be considered to reduce diagnostic delay and irreversible visual loss.