When he was nine, the mark began to grow into a fleshy tumour. By his 12th birthday it had grown to the size of a fist and Yang received surgery to remove it.
However, it quickly started to grow because Yang suffered from neurofibromatosis.
The giant tumor greatly affected Yang's life and left him lying down or sitting in bed all day long.
The team of medics who removed the giant growth in 2014 consisted of nine doctors, with the operation lasting 16 hours. During the surgery, Yang received 5000ml of blood.
Neurofibromatosis (NF) refers to a group of inherited disorders that carry a high risk of tumour formation, particularly in the brain. NF has an autosomal dominance pattern of inheritance: meaning if one parent carries the neurofibromatosis gene, his or her children have a 50% chance of developing the condition as well. However, about half of the cases arise from a spontaneous genetic mutation with none of the parents carrying the gene.
The types of Neurofibromatosis include:
- Neurofibromatosis type I formerly known as Von Recklinghausen disease, in which the nerve tissue grows tumors (neurofibromas) that may be benign and may cause serious damage by compressing nerves and other tissues.
- Neurofibromatosis type II, in which bilateral acoustic neuromas (tumors of the vestibulocochlear nerve or cranial nerve 8 (CN VIII) also known as schwannoma) develop, often leading to hearing loss.
- Schwannomatosis, in which painful schwannomas develop on cranial, spinal and peripheral nerves.