Intraocular leiomyoma is a benign smooth muscle tumor. First recognized before the era of immunohistochemistry, uveal leiomyomas have been described in case reports and small case series. We add 3 new cases, for a total of 80. Of these, there were 29 men and 51 women. The mean and median ages were 35.8 and 30.5 years respectively, with a range of 8 to 80 years. Curiously, ciliary body tumors were more common in females, whereas iris and posterior choroidal leiomyomas were more prevalent in males. Infrequently associated with systemic fibroids, nuclear expression of sex steroid receptors was inconsistent. Iris and posterior choroidal leiomyoma were predominantly amelanotic, while 40% of ciliary body leiomyomas were brown. Two-thirds of the leiomyomas blocked transillumination partially or completely, a feature shared by uveal melanoma. In general, low-frequency ultrasound imaging reveals low to moderate internal reflectivity; however, high-frequency anterior uveal ultrasound was used to localize a leiomyoma as resident in the suprachoroidal space with an overlying layer of intact choroid. In the few cases examined by physiologic imaging, increased metabolic activity (typically associated with malignancy and inflammation) has been noted. We found that pigmented uveal leiomyomas can be clinically identical to melanoma. Therefore, histopathology with immunohistochemical staining for smooth muscle actin was the most reliable diagnostic method to differentiate pigmented uveal leiomyoma from melanoma. Treatment is governed by the clinical diagnosis, tumor size and location, as well as prognosis for vision and globe preservation.
Keywords: actin; benign; immunohistochemistry; leiomyoma; melanoma; uvea.
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