[Conjunctival fibrous histiocytoma simulating atipical pterygium in the Amazon region: case report].

An inedited case in the Brazilian literature of conjunctival fibrous histiocytoma discovered during a wide scale community project accomplished by the team of the Center of Reference in Ophthalmology of the Hospital das Clínicas da Universidade Federal de Goiás in the Amazon region is reported. A 38 year-old caucasian woman presented with a vascularized lesion on the medial portion of the bulbar conjunctiva and caruncular region of the right eye with extension for the limbus and invading about 2 mm of the medial cornea resembling a pterygium. Pathologic findings revealed that the lesion was constituted by spindle-shaped cells, with storiform arrangement, and large histocytelike cells. The immunohistochemistry revealed strong positivity for vimentin and the neoplastic cells were negative for AE1/AE3, HMB 45, S 100 protein. The histopathologic diagnosis was fibrous histiocytoma. The evolution demonstrated the tumoral growth and the possibility of a malignant lesion.