Optimizing diagnostic success for vitreoretinal lymphoma

Abstract

Aims/Purpose: To determine the diagnostic yield and pathological entities in a retrospective cohort of diagnostic vitrectomy patients.Methods: A retrospective cohort of diagnostic vitrectomy samples submitted to a tertial referral hospital pathology laboratory was identified by database search. The specimen submission protocol for this cohort consisted of two components: (i) intraoperative preparation of a neat vitreous aspirate as well as submission of the casette washings in RPMI and (ii) laboratory triage of each sample for microbiology culture, flow cytometry, cytological assessment and cell block preparation.Results: A total of 133 diagnostic vitrectomy samples were submitted between November 2015 and January 2022 (mean age 74 years, 0.8 M:F). A diagnostic report resulted in 132 (99.2%) of cases. Benign diagnoses (infectious and non‐infectious vitritis, degenerative or reactive changes, haemorrhage) were found in 88 of the cases (66.1%), while 20 cases (15%) were malignant. Of the malignant diagnoses, 18 (13.5%) were vitreoretinal lymphoma (17 diffuse large B cells; 1 T cell) by cytology and flow cytometry. The other two malignant diagnoses consisted of metastatic adenocarcinoma and metastatic cutaneous melanoma. 24 cases (18%) were classified as atypical, consisting of a lymphocytosis without demonstrable clonality by flow cytometry.Conclusions: This intraoperative and laboratory protocol maximizes the sample for all diagnostic tests required to discern infectious, inflammatory and malignant causes of increased vitreous cellularity. Importantly, the protocol allows for immunophenotyping of vitreoretinal lymphoma by flow cytometry and immunohistochemistry to WHO classification standards, essential for treatment and surveillance decision‐making.