Mesothelioma Information

Sarcomatoid mesothelioma is the least common type of mesothelioma cancer cell. In order to diagnose a case of sarcomatoid mesothelioma, a biopsy is required. A type of diagnostic surgery, a biopsy involves the removal of a section of suspect tissue for examination by a histopathologist.

Sarcomatoid mesothelioma cancer cells have an irregular oval shape and a nucleus that is not as clearly distinguishable as epithelioid nuclei, when viewed under high magnification.

Cancer cells often have an irregular oval shape, making it possible for a case of sarcomatoid mesothelioma to be misdiagnosed as some other type of malignancy. Sarcomatoid carcinoma and sarcoma are two cancer types that are commonly misdiagnoses of sarcomatoid mesothelioma patients.

Sarcomatoid Mesothelioma and Sarcomatoid Carcinoma

As rare as sarcomatoid mesothelioma is, it can often be confused with a variety of other types of cancers because of the commonality of the sarcomatoid appearance. Sarcomatoid mesothelioma is often misdiagnosed as a type of sarcomatoid carcinoma. A carcinoma is any type of cancer arising from the epithelial cells of the body.

Patients suffering from sarcomatoid carcinoma of the lung often present similar symptoms to patients suffering from sarcomatoid mesothelioma of the pleura: chest pain, fluid buildups within the pleural space (pleural effusions) and respiratory difficulties. Although sarcomatoid cancers can appear throughout the body, they are seldom found in the lungs; as few as 1.3% of all lung carcinomas are of the sarcomatoid variety. When lung sarcomatoid carcinomas do occur, they are four times as likely to occur in men as women. Smokers also face increased risk of developing a sarcomatoid carcinoma of the lung.

The sarcomatoid carcinoma that is most commonly confused with sarcomatoid mesothelioma is pulmonary sarcomatoid carcinoma.

Sarcomatoid Mesothelioma and Sarcoma

Sarcoma is another type of cancer that is often mistakenly diagnosed for people suffering from sarcomatoid mesothelioma. Simply stated, a sarcoma is a type of cancer of the bone, fat, muscle, cartilage or blood vessels (connective or supportive tissue). Although bone tumors are also referred to as a type of sarcoma, they have different characteristics to the connective/supportive tissue sarcomas and are therefore placed in a separate category and treated in a different manner.

When sarcoma cancer arises from the pleural tissue, it can be difficult to differentiate from a sarcomatoid mesothelioma of the pleura. The appearance of sarcoma cancer cells can be similar to sarcomatoid mesothelioma cells when viewed under high magnification. Typically, a diagnostic technique called 'staining' (histochemistry) is used to aid in differentiating one cancer from the other; however, staining of the tumor cells often provides similar results, adding to the overall confusion. In such cases, a histopathologist must carefully compare both the appearance and the staining of the cells in order to distinguish between a case of sarcomatoid mesothelioma and sarcoma.

Epithelioid and Biphasic Mesothelioma

There are three histological categories of mesothelioma cancer cells: epithelioid mesothelioma, sarcomatoid mesothelioma and biphasic mesothelioma.

Epithelioid mesothelioma is the most common type of mesothelioma cancer cell. Like sarcomatoid mesothelioma, epithelioid mesothelioma has a somewhat unique cellular pattern. When viewed under high magnification, epithelioid mesothelioma cells have a fairly distinct nucleus.

Biphasic mesothelioma is the second most common type of mesothelioma cancer cells. Unlike sarcomatoid and epithelioid mesothelioma, biphasic mesothelioma does not have a unique cellular pattern unto itself; rather, biphasic mesothelioma consists of a mixture of epithelioid and sarcomatoid mesothelioma cells.