A LEIOMYOMA OF THE IRIS DOCUMENTED BY IMMUNOHISTOCHEMISTRY AND ELECTRON-MICROSCOPY

Purpose: To report an iris leiomyoma documented in accordance with tod ay's stricter diagnostic criteria. Methods: Light microscopy, immunohi stochemistry and electron microscopy were performed on the 3 mm ball-l ike, greyish-white vascularized tumour of the iris, close to the sphin cter pupillae. Results: Light microscopy of the extirpated neoplasm sh owed the characteristic appearance of a leiomyoma with densely packed spindle-shaped cells, with oval nuclei and granular cytoplasm, On elec tron microscopic examination the tumour exhibited the characteristic f eatures of a smooth muscle neoplasm, The immunohistochemistry was cons istent with a myogenic tumour because the tumour cells were positive f or smooth muscle actin and desmin, but negative for S-100 and melanin. Conclusion: The case illustrated the necessity of performing ancillar y procedures such as electron microscopy and immunohistochemistry to s ubstantiate a correct, although rare diagnosis.