A 34-year-old man presents to your office complaining of increasing pain in his hip and thigh. He reports that as a child, he was diagnosed with a bony growth in the area of his hip, but it never gave him trouble so no intervention was undertaken. For the past 3 months, he has been experiencing increasing deep-seated pain in this area, without history of trauma. He has had some mechanical symptoms as well with clicking and a gradual decrease in motion of his hip. He denies weakness, numbness, and tingling distally. X-rays of the femur are shown in Figure 8–20A and B.

Figure 8–20 A–B

What is particularly concerning about this patient’s history and imaging?

A. Potential for malignant transformation

B. Potential for osteonecrosis

C. Potential for infection

D. Potential for permanent compressive neuropathy

Discussion

The correct answer is (A). The patient’s radiographs reveal evidence of a proximal femur osteochondroma. After years of being symptom-free from this lesion, he has started to develop pain. This finding is concerning for malignant transformation of the lesion, which should not become painful or grow after skeletal maturity. There is no indication of osteonecrosis or infection, and he denies numbness, tingling, and weakness indicating that the lesion is likely not compressing nerves in the area. Malignant transformation of osteochondroma, although rare, is usually to a low-grade chondrosarcoma and must be monitored for.

Clear-cell chondrosarcoma is a rare subtype that has predilection for which location?

A. Flat bones: ilium and scapula

B. Pelvis and sacrum

C. Posterior elements of the spine

D. Epiphysis of long bones

Discussion

The correct answer is (D). Clear-cell chondrosarcoma is a rare subtype of chondrosarcoma, a malignant cartilage tumor. It occurs in the epiphysis of long bones, most commonly in the proximal humerus and proximal femur. It occurs in a slightly younger age group than conventional chondrosarcoma. On x-ray, a radiolucent, round, epiphyseal lesion is seen which can sometimes be mistaken for a benign chondroblastoma. Chondroblastomas usually are associated with pain, and significant bony edema around the lesion seen on T2-weighted images that are generally not seen with clear-cell chondrosarcoma.

You are seeing a patient in postoperative follow-up after hemipelvectomy and reconstruction for grade 2 chondrosarcoma. What is true regarding her longterm survival and prognosis?

A. If the tumor recurs locally, it will always increase in grade

B. Survival rate is improved with postoperative radiation therapy

C. The possibility of late progression of the disease requires long-term follow-up

D. Dedifferentiated tumors have similar survival rates and prognosis when compared with lower grade tumors

Discussion

The correct answer is (C). Long-term surveillance for both local recurrence and metastases to the lungs is recommended after chondrosarcoma resection, due to its propensity for late progression. When chondrosarcoma recurs locally, about 10% to 30% of the time the tumor increases in grade. Radiation therapy plays no role in traditional chondrosarcoma management. Overall survival depends on the grade of the tumor, with rates listed below.

Objectives: Did you learn...?

Subtypes of chondrosarcoma?

Staging and prognosis of chondrosarcoma?