Of the more than 200 different types of cancer known to man, several are classified as rare types of cancers insofar as the number of individuals affected by these types of cancer is concerned. Unfortunately, because of the slowly-developing nature of cancer it is possible that many individuals already have the condition but are still not manifesting the signs and symptoms specific for such types of cancer. Nevertheless, here are the top 5 rarest cancers you may want to know.
According to Mesothelioma Help.Org (you can visit their website at https://www.mesotheliomahelp.org) mesothelioma is considered as a rare type of cancer that primarily affects the pleura or the epithelial tissues that line the outer surface of the lungs. While it is true that more than 80% of all mesothelioma cases are brought about by exposure to asbestos whether directly or indirectly, its unusually long carcinogenesis makes it exceptionally difficult to track the actual number of individuals who may already have this type of cancer. According to experts, it takes an average of 40 years from the time the individual has been exposed to asbestos until the first manifestations of clinical mesothelioma appear. The worldwide incidence rate of mesothelioma is at 1 to 6 for every 1 million population with the highest in western countries at a staggering 7 to 40 per 1 million.
This type of cancer is one of the most aggressive cancers of the skin. Unlike other types of cancer, Merkel-cell carcinoma is induced by a type of virus known as Merkel cell polyomavirus or MCV. While MCV produces about 80 percent of all Merkel cell carcinoma, it is the remaining 20 percent that health experts are particularly concerned about as it comes with exceptionally high rates of genome mutation. What this means is that, with UV exposure, the already-malignant Merkel cell undergoes a series of genetic mutations that make it more difficult to treat and eradicate. Every year, only 1,500 new cases are registered in the US alone. Globally, it accounts for 7 in every 1 million population.
Desmoplastic Small-Round-Cell Tumor
Primarily affecting the abdomen, desmoplastic small round cell tumor can also affect the peritoneum as well as the lining of the spinal cord, the chest wall, the diaphragm, the reproductive organs, and the skull, among others. The cancer cells can travel to the liver, brain, bones, lungs, and lymph nodes. Desmoplastic small round cell tumor mostly affects young boys. While it is rare to see this type of cancer in females, when it does present itself, it is often misdiagnosed as ovarian cancer. The exact cause of DSRCT is not known, although research suggests that it is the result of chromosomal translocation. Desmoplastic small round cell tumor is so rare that current estimates put its incidence rate at somewhere between 0.5 and 1 per 1 million population.
Since 1959 there have only been roughly 1,000 documented cases of mesenchymal chondrosarcoma, a type of rare cancer that primarily affects the cells that make up the cartilage. What is very menacing about this tumor is that it grows rapidly and has the propensity to spread, forming cancer in different organs of the body. About 65 percent of the cases have their origins from the cartilage tissues found in the spine, the jaw, and the ribs. The remaining third of cases have been identified to have originated from muscles and fat suggesting other mechanisms to be involved.
Hepatosplenic T-Cell Lymphoma
This type of lymphoma accounts for less than 5% of all types of lymphomas. The main pathologic feature of hepatosplenic T-cell lymphoma is the proliferation and infiltration by cytotoxic T-cells on the liver and spleen and can typically involve the bone marrow. What happens is that the immature cytotoxic T-lymphocytes express a type of T-cell receptor that allows the lymphocyte to attach and infiltrate the target organs. What is surprising is that this type of cancer is mostly seen in immunosuppressed individuals who have received solid organ transplants.
There are many other types of rare cancers, but these are generally considered as the world’s top 5. Unfortunately, because of the unique nature of cancers, it is possible that even rarer oncologic entities exist.