Deciduoid mesothelioma is a rare subtype of mesothelioma composed of an epithelial cell type. Most cases have occurred in young women with peritoneal mesothelioma, and like other types of mesothelioma, they are difficult to treat.
About Epithelioid Mesothelioma
Epithelioid mesothelioma is one main classification of this cancer by cell type. The epithelial type accounts for more than half of diagnosed cases. Epithelial cancer is easier to treat than sarcomatoid, the next most common type.
Because epithelial cells adhere together strongly, they are less likely to spread to other parts of the body. These cells will eventually metastasize (spread to other parts of the body) but do so more slowly than sarcomatoid mesothelioma.
What Are Deciduoid Cells?
These cells are called deciduoid because they look similar to cells seen in early pregnancy. In the early stages of pregnancy, hormone shifts trigger cellular changes in the uterus. The cells lining the organ change shape and purpose. This change helps the placenta develop and pregnancy progress normally.
After this shift occurs, the cells and lining of the uterus are called decidua; however, deciduoid mesothelioma cells are not the same. Instead, they resemble the uterine cells.
Histologically, patients with deciduoid mesothelioma have large, polygonal, or ovoid cells with well-defined cell borders and single or multiple nuclei.
Facts About Deciduoid Mesothelioma
- Deciduoid cells are a sub-type of epithelial cells. Mesothelioma comprised of deciduoid cells is extremely rare.
- Since first described in 1985, just 25 cases have been reported in the literature.
- The youngest female patient with a deciduoid mesothelioma diagnosis was just eight years old.
- Mesothelioma is overwhelmingly more common in older men; however, deciduoid mesothelioma most often strikes young women. It is possible to see deciduoid mesothelioma in older men and women.
- Another unusual characteristic of deciduoid mesothelioma is the half-and-half distribution between pleural and peritoneal deciduoid mesothelioma. With other cell types, about 75% of cases are pleural.
- Because of the way it forms and because it so often afflicts young women, many experts believe this mesothelioma is unrelated to asbestos exposure. Asbestos exposure causes the vast majority of mesothelioma cases. If this is correct, deciduoid mesothelioma is quite unusual.
Symptoms of Deciduoid Mesothelioma
The symptoms of this type of mesothelioma depend on where the cancer forms. For patients with pleural deciduoid mesothelioma, symptoms often include shortness of breath, coughing, and chest pains.
In the few cases of young women who developed peritoneal deciduoid mesothelioma, symptoms included:
- Abdominal pain
- Abdominal distension
- Fluid buildup in the abdomen
Causes of Deciduoid Mesothelioma
This type of mesothelioma is so rare that it is difficult to determine the causes. Many experts believe this type is not entirely related to asbestos exposure.
For most other types of mesothelioma, asbestos is the predominant risk factor; however, that does not seem to be the case with deciduoid mesothelioma. Only about one-third of people diagnosed ever encountered asbestos. Asbestos exposure likely causes this form of mesothelioma in older patients with the pleural form.
One hypothesis on the cause of this mesothelioma is that hormones are related to deciduoid mesothelioma. More than half of reported cases were in women. In two of those cases, the women were pregnant. It may be hormonal imbalances that trigger cancer development; however, few tests support this hypothesis.
Deciduoid mesothelioma diagnosis is problematic because it is so rare. It also closely resembles other illnesses, including more common types of peritoneal mesothelioma, a cancer that is also rare.
Many symptoms of peritoneal mesothelioma are similar to more common conditions like irritable bowel syndrome, including bloating, indigestion, and abdominal pain.
Even when mesothelioma is diagnosed, it can be hard to determine if someone has deciduoid mesothelioma specifically. The amount of the tumor that resembles the decidua varies by patient, making diagnosis even more difficult.
Another complication is the tumor often resembles another type of mesothelioma, pseudotumoral deciduosis.
This type of tumor may occur in pregnant women when they are pregnant; however, these tumors are not cancerous, though misdiagnosing mesothelioma as pseudotumoral deciduosis can be serious. A mistaken diagnosis can delay the life-saving treatment required for mesothelioma.
Treatment of Deciduoid Mesothelioma
As with all types of mesothelioma, treating deciduoid tumors is difficult and rarely curative. It is often diagnosed in later stages when it is well-developed and spread.
Surgery may be an initial treatment choice for tumor removal, but surgery may not be a viable option if the cancer has spread to other parts of the body.
Multi-modal treatment is the most common choice. This treatment approach uses several strategies to try to reduce the size and number of tumors. Multi-modal treatments generally use surgery, chemotherapy, and radiation in some combination.
A surgeon can remove the bulk of a tumor, while radiation and chemotherapy shrink tumors or eliminate remaining cancer cells after surgery.
What Is the Prognosis for Deciduoid Mesothelioma?
Unfortunately, the prognosis for deciduoid mesothelioma is typically not positive. Survival rates are low, with a shortened life expectancy for most patients.
With so few cases available to study, it is difficult to estimate life expectancy; however, only about one-third of deciduoid mesothelioma patients survived a year after a diagnosis.
According to a meta-analysis study patients with tumors that present highly aggressive clinical behavior have a mean survival rate of seven months. Patients with tumors that exhibit less aggressive clinical features have a mean survival rate of twenty-three months.
Treatments can extend life for some. For others, treatment simply reduces pain and increases mobility, generally improving the remaining quality of life.
Diagnosing rare subtypes of mesothelioma is important. Each variation of this rare cancer is unique and presents different treatment challenges. If you ever feel uncomfortable with a diagnosis, seek a second opinion.Get Your FREE Mesothelioma Packet
Page Medically Reviewed and Edited by Pinar Kanlikilicer, PhD
Dr. Pinar Kanlikilicer has a PhD in Biomedical Engineering. She completed her 5-years of postdoctoral training in the Department of Experimental Therapeutics at MD Anderson Cancer Center. She is currently working in the field of cancer as a research scientist.