<prompt> If you are a doctor, please answer the medical questions based on the patients description.my dtr has a 5cm tumorlesion in her L5 to S1 that has eroded her bone. had a biopsy and it s inconclusive. doctor at UCSF is taking her case to their tumor board on wed. it has well-defined margins, trabecular, wasn t bloody at time of biopsy, but he said bloody in bx report. her life has been turned upside down and we still don t have answers. she s 23 years old, a dancer, college student  <response>: I saw a similar case a year ago: CT an RMN seemed to show a tumor, but margins didnt infiltrate bone. After two negative biopsies, open surgery was performed to take a larger biopsy: again, no tumor. But cultural exam positive for staphylococcus aureus. In summary, it was a spondilodiscitis, an infection of intervertebral discs, generating a huge fibrosis mass containing bacteria. If the biopsy is negative, try cultural exams 