Tenosynovial giant cell tumor presenting as a parotid gland mass: Expanding the differential diagnosis of giant cell-rich lesions in salivary glands.

Tenosynovial giant cell tumors (TGCT) are rare benign soft tissue tumors affecting mostly young adults. The most common affected sites include the knee, ankle, elbow, shoulder, and fingers. The temporomandibular joint is occasionally affected. Herein, we report a case of a 31-year-old Caucasian male who presented clinically with a parotid gland mass. The initial clinical and radiological work-up failed to reveal any involvement of the adjacent temporomandibular joint. Fine-needle aspiration revealed a cellular tumor composed of mononuclear and multinucleated giant cells with fibrosis and hemosiderin deposition. This was subsequently found to be a TGCT arising from the temporomandibular joint. Giant cell-rich lesions are uncommon in salivary glands. Herein, we describe the cytomorphology and clinico-radiographic features of this tumor with emphasis on the differential diagnosis of giant cell-rich lesions presenting in salivary glands. Despite its rare occurrence, this entity should be considered when giant cells are prominent in specimens acquired from this location.