Hi, Thanks for writing in. A pilonidal cyst is a condition which occurs in the skin over the gluteal cleft due to low intensity chronic irritation. This is treated by wide excision and I understand that your friend has got it done. The treatment of excising it till the tailbone is as recommended and his doctor gave him the right treatment. Unfortunately it has turned out as a squamous cell cancer in the biopsy report and this might require aggressive treatment. Multi modality treatment approach might be required. Since surgery is done this might be followed up by chemotherapy and radiation therapy depending on the aggressiveness of the cancer. It is being found that radiation therapy works better for squamous cell cancer of the pilonidal cyst. Please do not worry.