Epithelioid osteosarcoma of the jaw

Osteosarcoma of the jaw: report of 3 cases (including the rare epithelioid variant) with review of literature

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).

Epithelioid Osteosarcoma of the Maxilla

Epithelioid osteosarcoma is an uncommon variant; only 4 cases have been reported in the jaw area, 2 of which were in the maxilla. A 22-year-old woman, in the eighth month of pregnancy, presented to the oral surgery clinic with a mass in the right maxilla that had rapidly expanded over the past 3 months. Computed tomography scans showed an ill-defined sclerotic destructive lesion that formed bone matrix in its soft tissue extension. Microscopic examination of the lesion revealed malignant epithelioid cells with osteoid deposits. The tumor cells were shown to have pale cytoplasm, vesicular nuclei, and prominent nucleoli and to undergo frequent mitosis. In addition, the tumor was positive for epithelial membrane antigen and vimentin and negative for AE1/AE3, Melan-A, CD30, synaptophysin, NSE, CD45, CD99, desmin, and myogenin. The final diagnosis was epithelioid osteosarcoma, which is a rare aggressive variant of osteosarcoma. Few cases of epithelioid osteosarcoma have been reported in the literature, and more studies are required to determine the clinical behavior of this tumor.