Pleomorphic adenocarcinoma of the ciliary body. Immunohistochemical and electron microscopic features

An 80-year-old man was evaluated for an epibulbar tumor on a phthisical eye. The initial biopsy diagnosis of the epibulbar tumor was poorly differentiated neoplasm. Exenteration of the phthisical eye and orbital contents showed an extensive pleomorphic adenocarcinoma of the nonpigmented epithelium of the ciliary body with extraocular extension. There was evidence of hyaluronic acid secretion and immunohistochemical staining was strong for vimentin, focal for epithelial membrane antigen and S-100 protein, and weak for neuron-specific-enolase. Electron microscopy demonstrated desmosomes between tumor cells, areas of thick, multilaminar basement membrane production surrounding individual tumor cells, and occasional intracytoplasmic intermediate filaments.