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Mesothelioma

Cell Types of Mesothelioma

Mesothelioma is classified into three histopathological subtypes; each type has its own unique characteristics that determine how the disease responds to specific oncological treatments.

Epithelioid

This is the most common subtype, and affects the epithelioid cells. It tends to be slower growing with a median survival of 19 months. Epithelioid mesothelioma is more likely to respond to chemotherapy.1

Image: Inai K. (2008). Microphotograph of epithelioid mesothelioma (H&E stain). Papillo-tubular structure is prominent. [Online Image]. Pathology of mesothelioma. 2008;13:60-64.

Sarcomatoid

Refers to mesothelioma tumours consisting of sarcomatoid cells. This cell type is more aggressive, it typically forms in multiple lesions and is more likely to spread to bone and nearby organs. Previously sarcomatoid mesothelioma was resistant to standard oncological therapy, but recent clinical trials have shown immunotherapy to be the most promising treatment. The median survival is 4 months.1,2

Image: Inai K. (2008). Microphotograph of sarcomatoid mesothelioma (H&E stain). Proliferation of spindle cells mimics true sarcoma. [Online Image]. Pathology of mesothelioma. 2008;13:60-64.

Biphasic

Also known as mixed mesothelioma, biphasic consists of at least 10% of both epithelioid and sarcomatoid cells. The percentage of epithelioid and sarcomatoid cells will impact the treatment options and prognosis.3

Image: Inai K. (2008). Microphotograph of epithelioid mesothelioma (H&E stain). Microphotograph of biphasic mesothelioma (H&E stain). The features of epithelioid mesothelioma and that of sarcomatoid mesothelioma are mixed within one tumor. [Online Image]. Pathology of mesothelioma. 2008;13:60-64.

References

  1. Asciak, R, George, V, Rahman, NM. Update on biology and management of mesothelioma. European Respiratory Review. 2021:30(159).
  2. Clopton, B et al. Sarcomatoid mesothelioma: unusual findings and literature review. Journal of Surgical Case Reports. 2022;2022(11)
  3. Røe OD. Mesothelioma diagnosis and prognosis are we moving beyond histology and performance status towards circulating biomarkers?. Journal of Thoracic Disease. 2018;10: 1956-1961.