Trans-corneal fine cannula aspiration: Rycroft cannula aspiration technique for sampling iris tumours.

Abstract

To demonstrate a novel surgical technique for the accurate diagnosis of iris lesions using a minimally invasive aspiration cannula. 12 consecutive patients underwent biopsy of iris lesions at the Ocular Oncology Service, Royal Hallamshire Hospital, Sheffield, UK. Samples were obtained using a novel technique called trans-corneal fine cannula aspiration. This comprised a 25-gauge, Rycroft cannula aspiration technique performed by a single surgeon and samples transferred into alcohol-based tissue fixative. A specialist ophthalmic histopathologist performed a histological analysis of the samples. On average, the size of the specimens obtained in theatre ranged from 1 mm to 1.5 mm (maximum dimensions). This sample size allowed an unequivocal histological diagnosis in all 12 cases. In this study, 10 patients were diagnosed as having iris melanoma, one patient with metastatic adenocarcinoma and one patient with pigmented adenoma. This simple iris tumour biopsy technique provides sufficiently large sample sizes to obtain a firm histological diagnosis in 100% of cases performed so far. The sample sizes permitted not only morphological interpretation but also ancillary investigations such as immunohistochemistry.