Fibrous mesotheliomas (pseudofibroma) of the scrotal sac: a light and ultrastructural study.

Fibrous mesotheliomas of the scrotal sac are described. Similar tumors have been previously reported as fibromas and pseudofibromas and have been considered to be non-neoplastic, reactive, fibrous lesions. Ultrastructural evidence for a mesothelial origin for these tumors is presented. The value of ultrastructural study in the classification of tumors arising in or on mesothelial lined surfaces is stressed.