Parotid gland chondroma masquerading as pleomorphic adenoma in fine needle aspiration cytology: A diagnostic challenge

Abstract

Chondroid neoplasm of parotid gland is extremely rare. Only a few cases of extraskeletal chondroma and one case of chondrosarcoma of parotid gland have been reported in the literature. The cytological features of parotid gland chondroma are not well documented. A 61-year female patient presented with a slow growing left preauricular mass for past 6 years. Computer tomography scan showed a well circumscribed mass in the superficial lobe of left parotid gland. Fine needle aspiration cytology (FNAC) showed uniform chondrocytes embedded in a chondroid matrix, and was diagnosed as pleomorphic adenoma. Histological examination of the excised specimen showed a benign cartilaginous tumor, consistent with chondroma. There was no epithelial or myoepithelial component on extensive search. Chondroma is an extremely rare tumor of parotid gland and can be misdiagnosed as pleomorphic adenoma on cytology examination. However, absence of epithelial and myoepithelial component can give a clue toward a pure chondroid neoplasm. This report highlights the diagnostic features of chondroma of parotid gland and its diagnostic pitfalls in FNAC.

Thymidylate synthase (TS) immunostaining in the diagnosis of the myoepithelial cells, basal cells, stratified epithelium cells, and associated tumors

“…There is a group tumors that originates from squamous epithelial cell (SEC), basal cell (BC), transitional epithelial cell (TEC) and myoepithelial cell (MEC) in various organs, including the squamous-cell carcinoma (SQCC), basal cell carcinoma (BCC), transitional-cell carcinoma (TCC), mixed tumor (MT), and other types of epithelial myoepithelial tumor (EMT) (3)(4)(5)(6). These are the most frequently diagnosed neoplasms and the most frequent cause of major cancer incidence worldwide.…”