[Morphology and histogenesis of so-called fibrous mesothelioma (submesothelial fibroma)].

Clinico-morphological characteristics of a tumor (6 observations) designated in the literature as fibrous mesothelioma are presented. This benign slowly growing tumor appears as an incapsulated dense nodule connected with the visceral layer of the pleura by a thin fibrous "pedicle". Microscopical structure of the tumor consists of outgrowths of monomorphic spindle-shaped cells, hyalinosis foci and abundance of blood vessels in some of its areas. Tumor cells ultrastructurally correspond to fibroblast indicating the connective tissue genesis of the so-called fibrous mesothelioma. This tumor should be distinguished from the group of mesotheliomas and be better called submesothelial fibroma.