Review Question - QID 213922

The patient is presenting to a community orthopedic surgeon with a lesion right iliac wing concerning for a malignancy, which necessitates referral to an orthopedic oncologist. Given the imaging, chondrosarcoma is most likely the culprit in this case.

Chondrosarcoma is a malignant sarcoma of chondroid tissue origin that presents in patients 40-75 years of age. Upon identification of a pathologic lesion concerning for a sarcoma, initial work-up should include systemic staging with a chest CT or chest X-ray as well as local staging with MRI and radiographs of the entire affected bone. Once there is a diagnosis of malignancy, referral to an orthopedic oncologist is necessary to ensure appropriate further workup and treatment. Chondrosarcomas are resistant to radiation and chemotherapy due to poor tissue perfusion and low mitotic rate with definitive treatment consisting of wide resection. However, in dedifferentiated chondrosarcoma chemotherapy may play a role in treatment, but this remains controversial.

Agafonoff et al. presented a case of a high-grade spindle cell sarcoma that presented as urinary retention to a urology clinic. The patient was seen in the treating urologist's clinic where retrograde pyelograms and cystoscopy revealed an extrinsic compressive lesion of the urinary tract. A follow-up CT scan of the pelvis revealed a 14 cm pelvic lesion with bladder displacement and compression and biopsy revealed a high-grade spindle cell sarcoma. The authors recommended that patients with a diagnosis of high-grade sarcomas should be treated at a referral center with a PET/CT scan performed prior to surgical excision.

Wurtz et al. retrospectively reviewed 68 patients that were diagnosed with primary sarcoma of the pelvic girdle. They reported that patients had an average of 7 months of pain symptoms that commonly mimicked non-neoplastic conditions that lead to misdiagnosis and treatment. They concluded that primary sarcomas of the pelvic girdle can be a diagnostic challenge with misdiagnosis leading to definitive treatment delays.

Figure A is an AP radiograph of the pelvis with a large and expansile calcifying lesion of the right iliac crest. Figures B and C are the coronal and axial CT images of the pelvis with a large expansile destructive lesion with calcifications centered on the right iliac crest. Illustration A is the histology of high-grade chondrosarcoma.

Incorrect Answers:
Answer 1: The patient's imaging is concerning for high-grade chondrosarcoma, which should be addressed by an orthopedic oncologist. Observation would be inappropriate given these findings.
Answer 2: The patient's imaging is concerning for high-grade chondrosarcoma, which should be managed with wide resection of the lesion.
Answer 3: Chemotherapy is generally ineffective against chondrosarcoma due to the low tissue perfusion and high content of myxoid matrix that limits the diffusion of cytotoxic agents.
Answer 4: Radiation has a limited role in the management of chondrosarcoma due to the low mitotic rate of the tumor.