Mesothelioma Sometimes Spreads to Unexpected Places

The asbestos-linked cancer mesothelioma is usually found in the pleural cavity around the lungs, or the peritoneal cavity encasing the abdomen. But several new studies are reminders of the fact that mesothelioma can spread (metastasize) to unexpected areas of the body.

An article in a recent issue of the Annals of Thoracic Surgery details the case of a 72-year-old woman who was successfully treated for malignant pleural mesothelioma, only to have the disease show up again 2 years later in her colon.  After receiving a diagnosis of malignant pleural mesothelioma, the patient underwent surgery, radiotherapy and chemotherapy.  But after two years of follow-up, she was admitted to the hospital with anemia and a CT scan found a large bleeding polyp in her colon.  Testing found the polyp to be metastatic mesothelioma.

In another recent case, doctors in China found malignant mesothelioma tumors in the chest, abdominal and pelvic walls of a 77-year-old woman. The doctors described the tumors as “giant masses” in the right flank and bilateral pelvic walls.  The diagnosis was made using CT scanning and MRI and was confirmed by pathology. The doctors say the case illustrates the need for “accurate investigation of the radiological features” in order to rule out – or to diagnose – mesothelioma in unexpected places.

According to a team of New Zealand doctors reporting in the journal Head & Neck, there have been 14 recorded cases of malignant pleural mesothelioma metastasizing to the mouth. In eight of the 14 cases, mesothelioma had spread to the tongue.  More than 60 percent of the cases of mesothelioma spreading to the oral cavity were of the epithelioid subtype. The authors warn that, because the incidence of mesothelioma is expected to continue to rise in many countries for at least a decade, physicians should be aware of the possibility of metastases to the mouth.

Finally, although there are no recorded cases of mesothelioma spreading the breast, it is possible for breast cancer to spread to the pleural cavity.  In such cases, warn the authors of a new study in the journal Histopathology, genetic similarities between breast and mesothelioma tumors could lead to a misdiagnosis of mesothelioma.  In particular, they say, the presence of a cell protein called calretinin in about 15 percent of breast cancers, as well as their tendency to display a cell structure close to mesothelioma, can be confusing from a diagnostic standpoint.

Sources:

Sibio, S, “Metastasis of pleural mesothelioma presenting as bleeding colonic polyp”, November 2011, Annals of Thoracic Surgery, pp. 1898-1901.

Shao, ZH, “Malignant mesothelioma presenting as a giant chest, abdominal and pelvic wall mass”, November 12, 2011, Korean Journal of Radiology, PP. 750-753.

Simon, SH, “Metastases to the oral region from pleural mesothelioma: Clinicopathologic review”, November 15, 2011, Head & Neck, Epub ahead of print.

Powell, G, “Expression of calretinin by breast carcinoma and the potential for misdiagnosis of mesothelioma”, November 2011, Histopathology, pp. 950-956.