Vitreous biopsy in uveitis of unknown cause.

We employed vitreous biopsy (needle aspiration and pars plana vitrectomy) in eight cases of patients with uveitis of unknown etiology. The results of cytological and culture analysis provided the diagnosis of disseminated histoplasmosis in one patient and ocular reticulum cell sarcoma in another patient. In six patients, no specific, treatable causative agents or conditions were identified. In two of these patients, however, various etiologic agents were ruled out, which provided a basis for excluding certain therapeutic options. Where chronic inflammatory cells were seen in the vitreous, the patients responded satisfactorily to conventional therapy; patients with acute or mixed acute and chronic inflammatory cells did less well. No complications resulted from the biopsy procedure. In cases of uveitis of unknown etiology, vitreous biopsy may provide identification of specific causative agents, as well as information useful for more precise histopathologic grouping of entities in this disease.