Giant cell-rich osteosarcoma of the parotid gland: An exceptionally rare entity at an unusual site.

Giant cell-rich osteosarcoma is a rare histologic variant of conventional osteosarcoma that affects mainly the extremities. Extraskeletal giant cell-rich osteosarcoma is therefore exceedingly rare. Here, we report the first case of this uncommon tumor involving the parotid gland in a 62-year-old male who presented with initial right jaw swelling. Radiologic work-up revealed a 6.2 cm mass involving the right parotid gland. Fine-needle aspiration cytology showed numerous multinucleated giant cells in a background of dyshesive epithelioid cells and rare clusters of spindle stromal cells, suspicious for malignancy. The subsequent excisional biopsy showed histopathologic features diagnostic for giant cell-rich osteosarcoma. Diagn. Cytopathol. 2016;44:1107-1111. (c) 2016 Wiley Periodicals, Inc.