Intramedullary cartilage forming tumors in the meta-diaphysis of the long bones can represent an enchondroma or a low-grade chondrosarcoma, with the latter requiring adequate surgical treatment. However, these two lesions have overlapping clinical and histological features and so they pose a diagnostic and therapeutic dilemma. The purpose of this study was to analyze the clinical outcome and to determine the relevant clinical and radiographic parameters for deciding on the treatment for these tumors.

We conducted a retrospective review of 73 patients who were treated for enchondroma or low-grade chondrosarcoma that was located in the metaphysis or diaphysis of the bones. There were 20 men and 53 women with an average age of 49 years (range: 18-80). The locations were the proximal humerus (n=34), distal femur (24), proximal femur (6), proximal tibia (3), proximal fibula (2), humerus shaft (2) and femur shaft (2). 41 patients were treated surgically and 32 patients were simply observed based on the following parameters at presentation; the presence of pain, the tumor length and radiographic evidence of endosteal erosion.

All of the 32 patients who were initially observed had no evidence of disease progression at the last follow-up (average: 3.2 years, range: 1.0-14.9). Forty (98%) of the surgically treated patients showed no recurrence at the the last follow-up (average: 4.3 years, range: 1.0-14.0).

The presence of pain, tumor length and radiographic evidence of endosteal erosion should be considered to determine the best course of treatment for intramedullary cartilage forming tumors in the meta-diaphysis of the long bones. With the appropriate selection of the patients, these tumors can be successfully treated nonoperatively.