Small Cell Mesothelioma

What Is Small Cell Mesothelioma?

Small cell mesothelioma is as a subtype of the epithelial cell type. But many mesothelioma tumors with small cell features are biphasic. That means the tumors contain a combination of epithelial and sarcomatoid cells.

This type of mesothelioma grows in a pattern like small cell carcinoma. But the tumors do not display the stream, ribbon or rosette patterns in the subtype of lung carcinoma.

Small cell mesothelioma tumors grow in the peritoneum (abdominal lining). They can also arise in the pleura (lung lining) or the pericardium (heart sac).

Most of these tumors are not made up entirely of small cells. Instead, they often also contain normal mesothelioma cells and other assorted neoplastic cells.

Roughly half or more of all cells in a tumor should display a small cell pattern for the tumor to qualify as this type.

Diagnosis of Small Cell Mesothelioma

Diagnosing this cell type is difficult. The reason is the cells look like other small cell neoplasms. Doctors must run immunohistochemical tests to differentiate between the diseases.

A single biopsy may not always contain a representative sample of the cells in the entire tumor. In one study, small cells made up 80% to 100% of the biopsy material. But only 15% to 20% of the full tumor. Doctors may retrieve several samples to make an accurate mesothelioma diagnosis.

After immunohistochemical staining, the tumor cells will test positive for different compounds. This helps the medical team narrow the diagnosis. Small cell mesothelioma and small cell carcinoma have similar-looking cells. But each disease reacts to different chemical markers.

Diagnosing the right type is vital because different cancers respond to different treatments.

Small Cell Mesothelioma Treatment and Prognosis

Developing a standard of treatment for small cell mesothelioma is difficult. Doctors have not reported many cases. So doctors must rely on standard mesothelioma treatment approaches.

Small cell lung cancer (SCLC) is more aggressive than other types of lung cancer. It is unclear if prognosis for small cell mesothelioma is different from other epithelial mesotheliomas.

Researchers in 2020 said small cell mesothelioma has similar cell morphology to SCLC. But it has a different immunohistochemical profile. They concluded that the rare variant has a poor prognosis with a mean survival of about 8 months.