Adenoma of the Ciliary Pigment Epithelium Misdiagnosed Clinically as Malignant Melanoma: A Case Report

Background: Adenoma of the ciliary pigment epithelium (CPE) is a rare intraocular neoplasm. Hence, it can present as a diagnostic challenge to both clinicians and pathologists. Here we are presenting a case report of a tumour that was initially misdiagnosed as malignant melanoma.

Case Report: A 38 year male patient presented with painless loss of vision of right eye and after clinical and radiological examination a diagnosis of malignant melanoma was reached. Partial irido cyclectomy was carried out to resect the tumour. Histologically, the lesion was composed of large epitheliod cells resting on PAS positive basement membranes with pigmented granules in their cytoplasm. Immunohistochemical examination revealed positivity for CAM 5.2 while the tumour was negative for AE1/AE3, S100 and HMB45. These morphological and immunohistochemical features excluded melanoma and the lesion was diagnosed as adenoma of CPE.

Discussion: Differentiating adenoma of CPE with choroidal melanoma is of utmost importance as adenomas have not been known to metastasize beyond the eye and local resection is curative. Melanomas may require enucleation. A correlation of clinical, histological and immunohistochemical parameter of this tumour is of prime importance in diagnosis of the tumor