Oncocytic Sialolipoma of the Submandibular Gland: Case Report and Literature Review

Sialolipoma is a rare benign salivary gland tumor, most commonly arising in the parotid gland. Its oncocytic variant is exceedingly uncommon, particularly in the submandibular gland. We report a 58-year-old woman presenting with a painless, enlarging left submandibular mass. Imaging revealed a heterogeneous fat-containing lesion with calcifications and suspicious lymphadenopathy, and fine-needle aspiration suggested a salivary gland neoplasm of uncertain malignant potential. The patient underwent submandibular gland excision with selective neck dissection. Histopathological examination confirmed oncocytic sialolipoma, and no recurrence was observed during 24 months of follow-up. A literature review identified only nine previously reported submandibular sialolipoma cases, several with oncocytic features. Preoperative findings, including calcifications and oncocytic cytology, may mimic malignancy. However, a well-circumscribed lesion composed of mature adipose tissue with salivary gland elements is diagnostic. Oncocytic sialolipoma of the submandibular gland is exceptionally rare. Despite its potential to mimic malignancy, it is benign, and complete excision provides definitive diagnosis and excellent prognosis.