Gigantic secondary pelvic chondrosarcomas treated with pelvic resection type I and III: A case report

INTRODUCTION: Patients with osteochondromatosis have a higher risk of malignant transformation into secondary chondrosarcoma. Chondrosarcoma at the pelvic region tends to present late and therefore pose a significant challenge for orthopedic surgeons because of the large tumor size, local extension, and complex anatomy with proximity to major neurovascular structure, intestinal and urinary tract. PRESENTATION OF CASE: A 44-year-old male presented the chief complaint of 15 years growing lumps on his left buttock and right groin, presenting with pain. Plain radiography revealed popcorn calcification at the left iliac wing and right superior pubic rami. Multiple exostoses were also visible. MRI showed a larger tumor diameter at the left iliac wing by 33 cm and right pubic rami by 13 cm. The histopathological result from the biopsy suggested low-grade chondrosarcoma. RESULT: The patient underwent pelvic resection type I and III in two-stage surgery. About one month after the first surgery, there was a postoperative infection. Debridement and antibiotic therapy resulted in a desirable functional outcome with an MSTS score 27 and no local recurrence sign during a one-year follow-up. DISCUSSION: Low-grade chondrosarcomas are not sensitive to radiation and chemotherapy; wide surgical resection is the mainstay of treatment. Chondrosarcoma at the iliac wing can be treated by pelvic resection type I, and further reconstruction needed to prevent pelvic tilting. Chondrosarcoma at pubic rami can be treated by pelvic resection type III. CONCLUSION: Proper patient selections, preoperative planning, and wide surgical margins with reconstruction provide desirable local control and clinical outcomes following pelvic resection.