Biopsy in indeterminate intraocular tumors

Abstract

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.