Orbital metastasis from prostatic carcinoma. Identification by immunocytology.

We report a case in which the diagnosis of prostatic carcinoma, metastatic to the orbit, was confirmed using an immunoperoxidase technique on cytologic specimens obtained by fine-needle aspiration. Computed tomography was valuable in localizing the tumor for biopsy and subsequent radiation therapy. The results of these studies correlated with the clinical history and other evidence of widespread metastatic disease. Ironically, the first evidence of malignancy in this patient was possibly also ophthalmologic, manifesting 14 months earlier with hemorrhagic retinopathy associated with thrombocytopenia. To our knowledge, this is the first report describing the combination of an immunoperoxidase technique with the fine-needle aspiration biopsy of an orbital tumor.