When should we biopsy a solitary central cartilaginous tumor of long bones? Literature review and management proposal.

Differentiation between benign and low-grade malignant cartilaginous tumors is a radiological and pathological challenge. Based on a literature review, we propose the following guidelines for the management of a solitary central cartilaginous tumor of long bones distinguishing three situations: 1. The tumor is considered to be aggressive and requires surgery if one of the following criteria is present: cortical destruction, Moth-eaten or permeative osteolysis, spontaneous pathologic fracture, periosteal reaction, edema surrounding the tumor on MR images, and soft tissue mass. Tumor biopsy followed by complete intralesional treatment is indicated. 2. The tumor is classified as active if two of the following active criteria are present: pain related to the tumor, endosteal scalloping superior to two-thirds of the cortical thickness, extent of endosteal scalloping superior to two-thirds of the lesion length, cortical thickening and enlargement of the medullary cavity. Tumor biopsy or excision is indicated. 3. The tumor is classified as possibly active if one of the previous active criteria is present. In such cases, bone scintigraphy and dynamic-enhanced MR imaging should be obtained. Radionuclide uptake superior to the anterior iliac crest at bone scintigraphy and early and exponential enhancement at dynamic-enhanced MR are considered as two additional active criteria. After these two examinations, if only one criterion is still present, the lesion can be regarded as possibly quiescent, and the following monitoring is suggested: first follow-up at three to six months and then once a year. Otherwise, if two or more active criteria are present, biopsy is recommended. 4. The tumor is considered quiescent and does not require surgery if no active or aggressive criterion is present. A radiological follow-up can be proposed.