Published online Oct 18, 2013. doi: 10.5312/wjo.v4.i4.327
Revised: June 7, 2013
Accepted: June 19, 2013
Published online: October 18, 2013
Core tip: We report a case of a 32 year-old male, admitted for a lytic lesion of the distal femur. Although open biopsy suggested fibrous dysplasia, clinical and radiological evaluation indicated malignancy. Histological examination of the excised specimen revealed central low-grade osteosarcoma. Central low-grade osteosarcoma is a rare, well-differentiated, sub-type of osteosarcoma, with clinical, imaging, and histological features in keeping with benign tumours. Thus, initial misdiagnosis is common, typically being mistaken for fibrous dysplasia. Central low-grade osteosarcoma is usually treated with surgery in isolation, with rare cases of distal metastases. However, regional recurrence is quite frequent after close margin excision.