Adenomatoid Mesothelioma

Any type of mesothelioma can have an adenomatoid growth pattern. Pleural, peritoneal or pericardial mesotheliomas may all feature an adenomatoid differentiation.

This type of mesothelioma can mimic several other types of tumors, including benign adenomatoid tumors and pleural metastases of adenocarcinoma. To correctly diagnose a patient, doctors will need to evaluate the patient’s clinical presentation as well as the unique histological features of the tumor.

Growth Patterns

These cells can be either flat or cube-shaped. In adenomatoid mesothelioma, the cells line small, gland-like structures.

As with other types of epithelioid mesothelioma, adenomatoid cells grow in a uniform pattern. Some tumors grow into microcystic structures. These patterns can have a lace-like appearance.

Adenomatoid growth patterns may coexist with other growth patterns in epithelial tumors, but are often the predominant pattern.

Lesions vs. Mesothelioma

Adenomatoid mesothelioma is not the same thing as an adenomatoid mesothelial lesion. These lesions grow in mesothelial cells, but these tumors have a different cellular makeup than malignant tumors and behave as benign lesions.

Lesions typically develop in the pelvic organs, but they can also arise in the pleura, mesentery or omentum. These benign tumors are very small and lack significant cellular abnormalities.

Diagnosis and Treatment

Malignant mesotheliomas are often diagnosed differently than lesions. The benign growths often develop in the genital tract (in both males and females), and they are often diagnosed incidentally during a pelvic surgery. A handful of these tumors have also been detected in the pleura during a debulking surgery for other lung masses.

However, when doctors diagnose a patient with malignant mesothelioma of the adenomatoid variety, the diagnostic process is the same as it is for any other type of malignant mesothelioma. Patients typically present with chest pain, shortness of breath and coughing. The oncologist then runs several imaging scans and biopsies that lead to diagnosis.

Benign adenomatoid tumors have also appeared in the following locations:

• Omentum
• Mesentery
• Pancreas
• Liver
• Bladder
• Mediastinal Lymph Nodes
• Adrenal glands

Because adenomatoid mesotheliomas look very similar to lesions, doctors need to look for specific markers to differentiate between the two conditions. Doctors primarily look for pleural thickening and pleural nodules. These two characteristics are typically absent in cases of benign tumors. To diagnose lesions, doctors look for fibrous stroma (soft tissues) and bland, well-defined cell borders.

While benign tumors are typically easy to remove through surgery, malignant tumors are more difficult to treat. The therapeutic options include surgery, chemotherapy and radiation therapy. However, one study showed that the mean survival of seven patients who received treatment for adenomatoid mesothelioma was 10 months from the time of diagnosis.