[Acquired ocular toxoplasmosis and immunosuppression of tumoral thymic origin]

A rare case of acute bilateral unifocal chorioretinitis in a 24 years old man is described. The patient had been followed for more than 3 years for a benign thymoma, detected by systematic radiography, that was initially operated on with success. Later, after recurrence of clinical signs a second operation was performed that revealed local invasion of the tumor which was histologically identified as a benign, lymphoid thymoma. Serological data permitted us to attribute the lesions to a sub-acute ganglionary toxoplasmosis, contracted five months before any ocular localization. A treatment including local corticotherapy and oral pyrimethamine and sulfonamide was undertaken. Healing of the retinal lesions occurred slowly. A complete study of the patient's immunity revealed an important deficiency of cell-mediated functions. The problem of diagnosis of opportunistic chorioretinitis is discussed. In patients with impairment of cellular-type immunity, the following are commonly observed: herpes group viral diseases (including cytomegalic inclusion disease), fungus diseases (candida, aspergillus, mucormycosis, cryptococcus), and, rarely, toxoplasmosis. The presence of specific serum antibodies is the most important element in making a diagnosis, considering that the ophthalmoscopic appearance and clinical course may vary.