Cytologic analysis of vitreous fluids: A retrospective review of our 24 years of experience

BACKGROUND Cytologic analysis of vitreous fluid is an important component in diagnosis of vitreitis. No standard reporting guidelines exist for these specimens. This study chronicles our 24 years experience and proposes a tentative diagnostic model. METHODS Retrospective cytology reports review and database study. Clinical indications, cytologic patterns, ancillary studies performed, and diagnoses were recorded. RESULTS 176 samples from 160 patients were included and main cytologic patterns are reflected in Table 1. Most fluids were negative for malignancy (88%) and patterns IIB (53%) and IIA (19%) were dominant. The non-diagnostic rate was 7%; atypical and suspicious categories represented <0.5% of fluids tested and only 2% were positive for malignancy (3 intraocular lymphoma and one melanoma). Clinical indications for fluid examination were infection/inflammation (59%), to rule out lymphoma (11%), amyloidosis (3%), melanoma (2%), or to investigate intraocular hemorrhage. Fungal elements were demonstrated in 7 cases. No viral inclusions were appreciated; however, one case was positive for HSV 2 by IHC and 2 were negative by PCR. One case had Gram + cocci. Flow cytometry studies were suboptimal in 6 fluids, negative for an aberrant lymphocyte population in 11, and positive for high grade lymphoma in 3 cases. Atypical, suspicious and positive for melanoma were reported in 3 samples. Amyloid was identified in 1 aspirate. CONCLUSIONS Cytologic analysis of vitreous fluid is a useful tool. Modern techniques like flow cytometry and PCR testing further expand the diagnostic possibilities. Standardization of diagnostic terminology will aid clinicians caring for patients suffering from ocular disease.