Purpose: To present the case of a patient with leiomyoma of the ciliary body and discuss the histological features and treatment of this rare intraocular tumor. METHODS/CASE REPORT: A 13-year-old boy presented with an asymptomatic tumor of the right eye. Visual acuity was 20/20 in both eyes. Ophthalmoscopy revealed an amelanotic, vascularized ciliary body tumor with exudative retinal detachment and partial transillumination. On ultrasound examination the tumor height was 8 mm and a low internal reflectivity was found. T2-weighted MRI scans showed a hypointense and T1-weighted scans a hyperintense intraocular mass with significant Gd-TPA enhancement. On the assumption that the diagnosis was consistent with an amelanotic ciliary body melanoma, a transscleral resection with adjuvant ruthenium-106 brachytherapy was performed. Visual acuity was 20/40 at 6 months after the operation.
Results: Routine stains revealed a pleomorphic tumor composed mainly of spindle cells with palisading in some areas and a prominent intercellular fibrillary background. Immunohistochemistry showed positivity for desmin, vimentin and actin. No reactivity with S-100 and HMB-45 was seen. Intracytoplasmatic filaments and micropinocytotic vesicles were detected by transmission electron microscopy. These findings were consistent with the diagnosis of a ciliary body leiomyoma.
Conclusion: Typical clinical features of leiomyoma include a dome-shaped configuration and translucency, but the final diagnosis can only be confirmed by histology with the aid of immunohistochemistry and electron microscopy. Though rare, leiomyoma should be considered in the differential diagnosis of amelanotic uveal tumors. Transscleral resection is the treatment of choice of anterior uveal leiomyomas, with a fairly good visual prognosis.