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.