Role of radiation therapy for pediatric upper extremity extraskeletal osteosarcoma: A case series.

Background: Extraskeletal osteosarcoma is an extremely rare disease, comprising less than 0.1% of all cancers diagnosed in the United States, of which less than 5% occur in the upper extremities. The management of two cases of pediatric upper extremity extraskeletal osteosarcoma is discussed.
Case Description: Two children initially noticed painless left upper extremity masses at the ages of 16 and 13, respectively. Following a period of several months, both lesions became symptomatic, necessitating operative intervention, which revealed giant cell-rich extraskeletal osteosarcoma; PET staging following gross total resection revealed no residual or metastatic disease in either patient. After extensive discussion with the patients and family, adjuvant chemotherapy was initiated for one patient, and adjuvant radiation therapy was initiated in both patients.
Conclusions: Despite the rarity of these tumors, the importance of radiation therapy has been established by current and ongoing studies such as the Children's Oncology Group study ARST0332. Radiation therapy remains an important component of the multimodality therapy comprising optimal treatment of this disease, despite the relative paucity of long-term outcome data derived from level I evidence.
(© 2019 Wiley Periodicals, Inc.)