Beyond the Bone: A Case Report and Review of Literature of Extraskeletal Chondroblastic Osteosarcoma of the Scalp

Abstract Extraskeletal osteosarcoma (EOS) of the scalp is an extremely rare malignant mesenchymal tumor that accounts for approximately 1 to 2% of all soft tissue sarcoma and 2 to 4% of all osteosarcoma. A 40-year-old man presented with painless swelling on the left side of the scalp for 3 months and right-side limb weakness for 10 days. The patient underwent surgery and the postoperative histopathology report was suggestive of chondroblastic osteosarcoma of the scalp. The patient received five cycles of Adriamycin-based systemic therapy. A response assessment imaging was done, which was suggestive of partial response. Osteosarcoma is chemotherapy- and radiotherapy-resistant tumor; hence, it requires a combined modality approach. Complete surgical excision with adequate surgical margin followed by adjuvant chemotherapy and radiation therapy proved to be one of the optimal treatment modalities.