Parosteal osteosarcoma.

In this retrospective clinical study, 6 cases of osteosarcoma of the bone have been analyzed. Five patients were with parosteal osteosarcoma and one with periosteal osteosarcoma. The study was performed at the Clinic for Orthopaedic Surgery in Skopje, Macedonia, from 1995 to 2005. This tumor represents 1.5% of all primary bone tumors treated at the Clinic in the 11 year period. The age of the 6 patients (2 female and 4 male) ranged from 8 to 39 years (average 23.8). The history analysis of the patients showed misinterpreted diagnosis in 50% of the cases, with 83.3% rate of local recurrence, 33.3% of metastases and 33.3% of mortality. Follow-up varied from 11 months to 9 years (average 4.5). The clinical and histopathological findings (identical with those reviewed in the literature) confirmed occurrence of two biologically different types of parosteal osteosarcoma: predominant type is originally "benign" but has a definite malignant potential, causing metastases after long symptom-free interval. The other type is highly malignant from the beginning. More radical surgery is recommended for the latter category of tumors, followed by chemotherapy. Compartmental, radical "en bloc" resection, followed by regular review of the patients, is recommended for the former (Tab. 1, Fig. 3, Ref. 20). Full Text (Free, PDF) www.bmj.sk.