Clinical outcome of parosteal osteosarcoma.
BACKGROUND
Parosteal osteosarcoma is a rare type of osteosarcoma with distinct characteristics. Clinical outcome of 21 patients was analyzed to assess the predictive relevance of surgical margin, intramedullary tumor extension and histologic grade.


METHODS
There were 5 mens and 16 womens with an average age of 26 years. Average follow-up was 9.1 years (range 2.5-22.1). Most common sites were distal femur (15) and proximal humerus (2). No patient presented with metastasis. Surgical margin was wide in 13 and marginal in 8. Intramedullary extension was seen in 10 patients (48%). Focal high-grade 2 and 3 tumors were seen in 11 (52%) and 3 (14%) patients respectively.


RESULTS
Twenty patients (95%) were alive without disease. Two (10%) had relapse, one with local recurrence and another with local recurrence and lung metastasis. Of eight marginal procedures performed, 2 turned out to have histologically tumor-positive margins, both of whom later developed relapses. All patients with histologically negative margins remained disease-free. Presence of intramedullary extension and focal high-grade tumor was not significantly associated with relapse.


CONCLUSIONS
A marginal but histologically negative margin of excision appears adequate for parosteal osteosarcoma. However, long-term follow-up is warranted for monitoring of rare incidences of local recurrences or distant metastases.
Department of Orthopaedic Surgery, Seoul National University College of Medicine, Chongno-Gu, Seoul, Korea.
Ilkyu
I
Han
Joo Han
JH
Oh
Yeong Gon
YG
Na
Kyung Chul
KC
Moon
Han-Soo
HS
Kim
D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000601:surgery; D001859:Bone Neoplasms / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005266:Femoral Neoplasms / Q000601:surgery; D005360:Fibula / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D006811:Humerus / Q000601:surgery; D007085:Ilium / Q000601:surgery; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D018365:Neoplasm, Residual; D018217:Osteosarcoma, Juxtacortical / Q000556:secondary / Q000601:surgery*; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery; D016896:Treatment Outcome