LAUSR

Osteosarcoma of the jaw (OSJ) is a rare malignancy, accounting for less than 1% of head and neck malignancies. OSJ can arise as a primary malignancy or secondary to locoregional radiation treatment. Radiologically, these tumors show large, destructive growth with periosteal reaction, which can suggest the diagnosis of osteosarcoma (OS). However, histology with demonstration of neoplastic, "lacelike" osteoid is the key to determining the diagnosis. Small tissue samples can complicate the diagnosis, especially in cases of high-grade OS with sheetlike growth and scant areas of immature osteoid formation. We report 3 cases of OSJ, including 1 rare case of epithelioid OS of the mandible, diagnosed at our hospital over a 6-month period: case 1: a 48-year-old male with history of Hodgkin lymphoma, who was treated with radiation and developed osteoblastic OS of the mandible 14 years later; case 2: a 79-year-old female with a history of fibrous dysplasia, who presented with a large destructive maxillary mass, which was diagnosed as histologically fibroblastic OSJ of the maxilla; and case 3: a 70-year-old male with radiation-induced high-grade epithelioid OS, which had been incorrectly diagnosed as poorly differentiated squamous cell carcinoma on a small biopsy specimen; this patient experienced recurrence with multiple neck nodules after treatment, underwent repeat resection, and was finally diagnosed with high-grade OS (epithelioid type).