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Mesothelioma Histology

Ongoing medical research is constantly expanding the existing body of knowledge for pleural mesothelioma, providing doctors with an extended understanding of the disease and patients with tailored treatment options. The anatomical study of mesothelioma cells, referred to as mesothelioma histology, has identified three major types of cells. Taking the classifications into consideration, medical professionals can in turn develop more accurate diagnostic options based on the examination of diseased tissue, an endeavor referred to as mesothelioma histopathology.

Histology, Histopathology and Mesothelioma

Pleural mesothelioma histology involves studying cell and tissue samples under a light microscope or electron microscope to closely examine the anatomy of the specimen. The cell sample must then be “fixed” with specific chemicals to prevent decomposition during extended examinations. Additional chemicals may be used to “stain” the cells in order to provide clearer observation.

The three different cell types designated by histological studies play a key role in mesothelioma histopathology. Histopathology aims to improve diagnostic techniques by pinpointing a diagnosis based on the microscopic makeup of diseased cells.

Since mesothelioma histology reveals three unique types of mesothelioma cells, doctors can make a more distinct diagnosis by considering the anatomical structure of cancerous cells extracted during a biopsy. Histopathologists diagnosing a pleural mesothelioma tumor look for specific trademarks indicated by mesothelioma histology to classify the case as epithelial, sarcomatoid or biphasic. 

Mesothelioma Cells

Epithelial cells are the most commonly identified cell type, accounting for 50 to 70 percent of all mesothelioma cases. These cells are uniform and well-defined, although they do pose a slight diagnostic difficulty due to their resemblance of adenocarcinoma, another cancerous cell unrelated to mesothelioma.

Sarcomatoid cells are the least frequently occurring cells, responsible for only 7 to 20 percent of total mesothelioma cases. Unlike epithelial cells, sarcomatoid cells are irregular and elongated, often resembling a spindle in shape. These cells often overlap within a pleural mesothelioma tumor and can be misdiagnosed as benign fibrous tissue when invaded by desmoplastic cells (a subset of sarcomatoid cells) or extended to other tissues.

Tumors may also be comprised of both epithelioid and sarcomatoid cells. This “mixed” type is known as biphasic mesothelioma and makes up 20 to 35 percent of total diagnoses. The cell mixture in biphasic mesothelioma is not randomly dispersed. Instead, cells tend to form groups throughout the tumor. As a result, it is necessary for histopathologists to take multiple samples from randomized locations throughout the tumor for an accurate diagnosis.

Sources

1. Galateau-Salle, Francoise. Pathology of Malignant Mesothelioma. Springer-Verlag London Limited: London. 2006.
2. Pass, I., Vogelzang, N., Carbone, M. Malignant Mesothelioma: Advances in Pathogenesis, Diagnosis, and Transitional Therapies. Springer: New York. 2005.