Desmoplastic Mesothelioma

What Is Desmoplastic Mesothelioma?

Desmoplastic mesothelioma is a unique type of the sarcomatoid form of mesothelioma. The term “sarcomatoid” describes cells that are long and spindle-shaped. While this subtype is less common, it is important to understand it, as it can be more serious than other forms of mesothelioma cancer. 

This variant is characterized by dense fibrous tissue and fewer cellular features. Unfortunately, it tends to have a poor outlook and can appear in all types of sarcomatoid mesothelioma.

Desmoplastic cells are not easily distinguished and do not show clear patterns. These types of mesothelioma cells create dense nodules of connective tissue in tumors, which can make diagnosis more difficult.

This rare form accounts for about 5% to 10% of all malignant mesothelioma cases. The main cause of this disease is exposure to asbestos, and it can develop in various types of mesothelioma cancer.

Diagnosing Desmoplastic Mesothelioma

When diagnosing mesothelioma, having a sample of tumor tissue, also known as a biopsy, is key. A biopsy helps determine the cell type and the best treatment options.

The fibrous parts of this tumor can sometimes hide variations in the cells, which can lead to misunderstandings in the diagnosis. Occasionally, doctors might mistakenly identify desmoplastic malignant pleural mesothelioma as fibrous pleurisy. Other possible misdiagnoses include pleural fibrosis, rheumatoid disease or spindle cell sarcoma.

Criteria for Diagnosing Desmoplastic Mesothelioma

• At least 50% of the tumor consists of nodules with dense fibrous tissue.
• There are areas with increased cell activity showing sarcomatoid features.
• Neoplastic spindle cells have spread to the lungs or chest wall.
• There is evidence of metastasis to nearby fat tissue, skeletal muscle or the lungs.
• The p53 tumor suppressor gene protein is present.

When desmoplastic mesothelioma spreads, it can sometimes appear less aggressive, making it easy for doctors to mistake the cells for benign fibrous tissue. Imaging scans, like CT or MRI, can be very helpful for pathologists to spot metastasis and correctly diagnose DMM in tough cases.

In 2017, researchers found a protein called GATA-3. This protein helps differentiate desmoplastic mesothelioma from sarcomatoid lung cancer. It is often present in many mesothelioma cases but usually absent in lung carcinoma cases. This discovery supports doctors in staging pleural mesothelioma.

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Symptoms of Desmoplastic Mesothelioma

Dense and fibrous areas in the lungs can lead to symptoms similar to pulmonary fibrosis, such as chest pain and fluid buildup. However, it’s important to note that these symptoms do not appear in every case of mesothelioma.

Common Symptoms of Desmoplastic Mesothelioma

• Anemia (low iron)
• Chest pain or a feeling of fullness in the abdomen
• Coughing up blood
• Fatigue and extreme tiredness
• Loss of appetite, nausea, and anorexia
• Low blood oxygen levels
• A persistent cough
• Prolonged hoarseness
• Shortness of breath
• Weight loss and weakness

The type of tumor cells does not change the symptoms of mesothelioma. For example, patients with pleural mesothelioma often experience shortness of breath, while those with peritoneal mesothelioma may have abdominal pain. If you notice any of these symptoms, it’s important to consult a health care professional for guidance and support.

Desmoplastic Mesothelioma Treatment

When it comes to treating desmoplastic mesothelioma, there are several options available, including immunotherapy, chemotherapy, and radiation therapy. These treatments work to target cancerous cells, helping to shrink tumors and prevent them from spreading. The choice of treatment often depends on the patient’s age and overall health.

One of the most promising first-line treatments is immunotherapy with nivolumab (Opdivo) and ipilimumab (Yervoy). Following this, chemotherapy with cisplatin and pemetrexed (Alimta) is commonly used.

Radiation therapy can also be beneficial, especially for reducing painful tumors in the chest wall. A recent case study from 2022 highlighted that nivolumab might be particularly effective for patients with sarcomatoid cell types, as these cells often have higher levels of PD-L1 compared to epithelial cells.

It’s important to note that surgery is not typically recommended for this type of mesothelioma because of its high risk of recurrence within a few months. However, there are rare cases where some patients with early-stage or localized tumors have experienced longer survival after surgery.

The main goals of these treatments are to alleviate symptoms, extend survival and enhance the quality of life for patients. For those dealing with fluid buildup in the lungs or abdomen, doctors often suggest procedures like pleurodesis or paracentesis to help manage this issue effectively.

Prognosis of Desmoplastic Mesothelioma

The prognosis for mesothelioma with desmoplasia can be challenging. This subtype is similar to other types of sarcomatoid cancer, making it tricky to diagnose. Many patients find they have advanced disease by the time they receive a diagnosis. Unfortunately, this can lead to a life expectancy of less than one year for those affected.

A comprehensive seven-year study looked at 255 patients with mesothelioma from 1982 to 1989. Researchers discovered 17 cases of the desmoplastic subtype. Among these, 11 were identified as sarcomatoid and six as biphasic, which includes both sarcomatoid and epithelial cell types.

The average survival time from the onset of symptoms to death was about 5.8 months for the sarcomatoid variant and 6.8 months for the biphasic variant. Other studies suggest that the average life expectancy may be around 3.8 months.

While these statistics can feel overwhelming, it is important to seek support and explore treatment options. Every patient’s journey is unique, and there are resources available to help navigate this difficult time.

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