Ultrastructural study of a benign localized pleural fibrous mesothelioma from a 22-year-old female had features of both epithelial cells as well as fibroblasts.
The findings support the concept of a mesothelial origin for this tumor.
Cancer 39:139-142, 1977.
OCALIZED FIBROUS MESOTHELIOMA" HAS "L occasionally been described as arising from the pleura.' Murray and Stout' reported its mesothelial features with tissue culture, and transitions between mesothelial and fibrous stromal elements have been observed by light microscopy. However, the predominantly fi- brous appearance of the tumor has resulted in a controversy regarding its histogenesis. 4 7 Recent ultrastructural observation^'*^^^*^^ of localized fibrous mesotheliomas have generally not supported a mesothelial origin, although Kay and Silverberg' have described cells with both epithelial and fibroblastic features.
A localized pleural fibrous mesothelioma (Fig 1 ) recently removed from a 22-year-old Japanese female provided an opportunity to study the ultrastructural features of this tumor. The presence of both epithelial and fibroblastic elements in the neoplasm supports a mesothelial histogenesis.
Methods
For light microscopy, the tissue was fixed in 10% formalin, embedded in paraffin, and stained with hematoxylin-eosin and alcian blue, and with Weigert's method for elastic fibers. Tissue for electron microscopy was fixed in 2.0%