Solitary (localized) pleural mesothelioma. A light- and electron-microscopic study

Area of Science:

• Oncology
• Pathology
• Cell Biology

Background:

• Solitary (localized) pleural mesotheliomas are rare neoplasms.
• Understanding the cellular origin and differentiation of these tumors is crucial for diagnosis and treatment.

Purpose of the Study:

• To investigate the histopathological and ultrastructural characteristics of benign solitary pleural mesotheliomas.
• To compare tumor cells with normal mesothelial and fetal stromal cells to determine their origin.

Main Methods:

• Light microscopy and electron microscopy were used to examine six solitary pleural mesothelioma cases.
• Comparative ultrastructural analysis with human and rat fetal mesothelial cells was performed.

Main Results:

• All studied lesions were benign, characterized by fibrous tissue with cystic spaces lined by round cells.
• Tumor cells exhibited features of fibroblasts, with scanty cytoplasmic organelles but presence of rough endoplasmic reticulum, mitochondria, fibrils, and polysomes.
• Ultrastructural similarities were observed between tumor cells and mesothelial/stromal cells of fetal rat pleura.

Conclusions:

• Solitary pleural mesotheliomas are likely derived from coelomic epithelium.
• The tumor cells appear to be undifferentiated or minimally differentiated fibroblasts with potential mesothelial lineage.