Objective: To describe an intraocular biopsy technique that allows accurate histopathologic diagnosis in cases of clinically unclassifiable uveal tumors.
Design: Retrospective noncomparative consecutive interventional case series.
Participants/methods: Intraocular biopsies were performed by a vitreous cutter either by a two-port clear cornea approach in 11 patients with unclassifiable iris tumors or by a three-port pars plana vitrectomy in 23 patients with unclassifiable choroidal tumors. Specimens were formalin fixed and paraffin processed. Hematoxylin-eosin and periodic acid-Schiff stains were performed in all cases, with additional immunohistochemical stains using the alkaline phosphatase, antialkaline phosphatase method in cases that could not be conventionally classified.
Main outcome measures: Clinical observation and histopathologic examination of intraocular biopsies.
Results: In 97% of cases (n = 33) a definite diagnosis could be established by the biopsy specimen. A melanoma could be diagnosed in 73% of cases (n = 8) of iris tumors and in 57% of cases (n = 13) of posterior intraocular tumors. Other diagnoses included nevus, metastasis, vasoproliferative tumor, hemorrhage, gliosis, and scleritis. Complications were encountered in four cases: a vitreous hemorrhage occurred twice, an inconclusive biopsy result, and an intraocular tumor spread occurred once, respectively. No increased tumor-related mortality was observed after a mean follow-up of 44 months.
Conclusions: Intraocular biopsy by a vitreous cutter allows the histopathologic examination of formalin-fixed paraffin-embedded tumor tissue. This increases the diagnostic accuracy, avoiding the risk of extraocular tumor spread seen with transscleral biopsy techniques.