Can you describe the medical condition and the failed treatments mentioned in the story of the Malegaon doctor's nephew?

According to Chapter 34, the nephew of the Malegaon doctor suffered from a bone-cyst, which is also referred to by its common name, Hadyavarn. This condition was described as a most difficult and extraordinary malady that caused the young boy immense pain and distress. The chapter explicitly states that a wide array of treatments were attempted without success. These included all native and foreign medical treatments, the expertise of many physicians and intelligent surgeons, and even surgery. All these efforts were exhausted, leaving the medical experts feeling helpless before the family turned to Sai Baba.