Japanese Doctors Report on Rare Variant of Malignant Mesothelioma
Although malignant pleural mesothelioma is a rare, incurable cancer caused by asbestos exposure, the disease is similar to many other cancers in the composition of the tumor cells. However, in the Journal of Thoracic Imaging, Japanese researchers reported an even rarer case of mesothelioma after treating a patient whose mesothelioma tumors had tissue that resembled that found in cartilage and bone.
Often called “asbestos cancer,” mesothelioma is a cancer of the mesothelial cells caused by breathing in asbestos fibers that become lodged in the thin membrane that lines and encases the lungs. Cases of mesothelioma continue to increase in Japan, and 2,500 to 3,000 new cases are diagnosed each year in the United States.
The 69-year-old male, building contractor had been exposed to asbestos for 48 years, and was diagnosed with malignant mesothelioma through a CT scan and a tissue biopsy. The man underwent extrapleural pneumonectomy , a complex surgery that involved the removal of his affected right lung and the associated parietal pleura and visceral pleura that line the lung.
The surgeons found that the tumor had compressed the right lung, and they could feel the hardened calcifications in the tumor and pleural tissue. Despite the removal of the tumors and cancerous tissue, the mesothelioma spread, and the patient died 19 months after surgery.
Symptoms of mesothelioma may not appear until up to 50 years after initial exposure to asbestos. However, after symptoms become apparent, mesothelioma may rapidly progress to cause life-threatening complications. The average mesothelioma survival time varies from 4 – 18 months after diagnosis.
The Japanese researchers, and other researchers, hypothesize that cells in the mesothelium, the lining of the lungs, have multipotency— in other words the potential of becoming any of several mature cell types, including bone.