Maffucci’s syndrome is a very rare form of enchondromatosis that combines multiple enchondromas in bones anywhere in the body with benign soft tissue tumors (known as hemangiomas), which are abnormal tangles of the blood vessels. This condition tends to appear in the hands and feet, and has a greater tendency toward malignant transformation than Ollier’s disease. Bone cancer in the skull and other types of cancer, including ovarian and liver cancer, have an increased risk of developing in individuals with Maffucci syndrome.

While the cause of this condition is unknown, many researchers believe that the condition may be associated with abnormalities that occur before birth when the two embryonic cell layers called the ectoderm and mesoderm are developing.