Immunocytochemical diagnosis as inflammation by vitrectomy cell blocks in patients with vitreous opacity

Purpose: To describe the clinical and cytopathologic characteristics in patients with vitreous opacity of unknown cause or preceding inflammation, diagnosed cytopathologically as inflammation. Design: Retrospective case series. Participants: Forty-three consecutive patients (61 eyes) who underwent vitrectomy for vitreous opacity of unknown cause or preceding inflammation and were diagnosed cytopathologically with inflammation at one institution in 6 years from 2005 to 2010. During the same period, 11 consecutive patients with vitreous opacity of unknown cause were diagnosed cytopathologically with lymphoma (large B-cell lymphoma) and were excluded from the study. Methods: Cell blocks were made by centrifugation of vitrectomy fluid and embedded in paraffin for immunocytochemistry. Main Outcome Measures: Cytopathologic and immunocytochemical diagnosis using vitrectomy cell blocks. Results: Histiocytes (macrophages), small lymphocytes, neutrophils, and eosinophils were predominant cells, with no atypical large cells on hematoxylineosin staining. Immunocytochemically, most predominant cells were CD68-positive histiocytes (macrophages), followed by CD3-positive T cells, but CD20- or CD79a-positive B cells were rarely present. Epithelioid cells, positive for CD68, were found in 4 patients with or without an established diagnosis of sarcoidosis, and giant multinucleated cells were found in 2 patients with suspected preceding self-limiting Vogt-Koyanagi-Harada disease, based on the presence of depigmented red fundi. Inflammation was diagnosed in 2 patients with vitreous opacity who had a preceding onset of brain lymphoma or systemic lymphoma. Conclusions: The presence of macrophages, combined with small T lymphocytes, was a major sign in intravitreal inflammation, manifesting as vitreous opacity. A simple technique of cytopathology and immunocytochemistry, using vitrectomy cell blocks, can be performed in most pathology laboratories. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.