CORRInsights®: Is Needle Biopsy Clinically Useful in Preoperative Grading of Central Chondrosarcoma of the Pelvis and Long Bones?
Enchondromas are classically asymptomatic incidental findings. However, if a patient presents with a complaint of atypical bone pain and imaging demonstrates a subtly aggressive central cartilage neoplasm in the bone, one must be concerned about degeneration of an enchondroma into a true low-grade chondrosarcoma. The clinician must carefully scrutinize the images and follow the patient through time to discern the behavior of the lesion. Unless the imaging tests clearly show signs of aggressive behavior (such as substantial or progressive endosteal scalloping, cortical breakthrough or broad zone of transition), the biopsy often will be useless, as the lesion is likely to have characteristics of a low-grade neoplasm. That is, it is effectively impossible to distinguish an enchondroma from a low-grade chondrosarcoma on biopsy alone. If there is progression over time, it is fair to assume that this lesion is a low-grade chondrosarcoma and aggressive curettage would be appropriate.
When a cartilage tumor undergoes malignant degeneration, the imaging usually makes this clear. Growth of the lesion or cortical compromise are signs of cancer, and when these are observed, the biopsy—though important—generally is only confirmatory; even if the biopsy reveals a lower grade lesion, wide resection is imperative, as the (false-negative) biopsy likely reflects sampling error.