A leiomyoma of the iris documented by immunohistochemistry and electron microscopy

Abstract

PURPOSE: To report an iris leiomyoma documented in accordance with today's stricter diagnostic criteria. METHODS: Light microscopy, immunohistochemistry and electron microscopy were performed on the 3 mm ball-like, greyish-white vascularized tumour of the iris, close to the sphincter pupillae. RESULTS: Light microscopy of the extirpated neoplasm showed the characteristic appearance of a leiomyoma with densely packed spindle-shaped cells, with oval nuclei and granular cytoplasm. On electron microscopic examination the tumour exhibited the characteristic features of a smooth muscle neoplasm. The immunohistochemistry was consistent with a myogenic tumour because the tumour cells were positive for smooth muscle actin and desmin, but negative for S-100 and melanin. CONCLUSION: The case illustrated the necessity of performing ancillary procedures such as electron microscopy and immunohistochemistry to substantiate a correct, although rare diagnosis.