Cancer is a large group of diseases that can start in almost any organ or tissue of the body. There are more than 100 types of cancer, and just over a quarter are considered rare, including all children's cancers. Approximately one in five people living with cancer in the United States are diagnosed with a rare cancer. Rare cancers are challenging for patients, doctors, and scientists alike. In fact, a few are so uncommon that no clinical trial results, meta-analyses, or treatment guidelines exist. While most rare cancers are aggressive, quick spreading, and offer up a grim prognosis, others are benign and can be treated effectively.
So, just how scarce are these little-known cancers, and how dangerous are they? Click through for a diagnosis.