Case Report: Transurethral Resection for Osteosarcoma of the Bladder

By: Jenna Carter, PhD
Posted: Thursday, June 16, 2022

A recent article published in the Journal of Medical Case Reports highlighted a rare case of osteosarcoma of the bladder and the clinical outcomes following treatment. Kensaku Nishimura, MD, of Osaka University Hospital, Japan, and colleagues performed a second transurethral resection of bladder tumor on a patient with a history of bladder cancer. They tracked the patient’s progress over 29 months and reported the patient was still alive and had no evidence of recurrence of the tumor.

“Osteosarcoma arising from the bladder is extremely rare, with only 38 cases reported to our knowledge. It is often detected owing to hematuria and is treated by surgery (for example, total cystectomy), radiation therapy, and chemotherapy; however, the prognosis is extremely poor,” stated Dr. Nishimura and colleagues.

An 83-year-old man with a history of bladder cancer underwent a routine cystoscopy for postoperative follow-up, and a 2-cm nodular mass was found on the right wall of the bladder. An abdominal computed tomography scan showed a mass with calcification, and a magnetic resonance imaging scan showed the tumor had high-signal intensity on diffusion-weighted imaging; however, no apparent muscle layer invasion was found. A transurethral resection of the bladder tumor was performed, and the tissue was examined for histopathologic diagnosis. The patient then underwent postoperative routine checks for 29 months.

Following surgery, microscopic examination of the resected tissue showed spindle-shaped or star-shaped cells with irregularly enlarged nuclei. Some of the cells also showed unnatural formations of osteoid and cartilage tissue. Immunostaining was performed, and the results were positive for desmin, smooth muscle actin, vimentin, Ki67, and p53 but negative for CD34, c-KIT, AE1/AE3, and p16. No urothelial carcinoma component was found, and no tumor was found in the systemic bone, so the patient was ultimately diagnosed with bladder osteosarcoma. After 29 months of postoperative follow up, no tumor recurrence was observed.

Disclosure: The study authors reported no conflicts of interest.

Journal of Medical Case Reports