Oncocytic Sialolipoma of Parotid Gland: Case Report and Literature Review

Oncocytic sialolipoma is a very rare tumor of which only three cases have been reported. This entity is considered to be a variant of sialolipoma which harbours oncocytic nodules within a well-circumscribed lipomatous mass. We report a parotid mass in 73-year-old female that was difficult to diagnose in imaging and on biopsy. Ultrasonography and MRI demonstrated a mass with features thought to be consistent with lipoma. Twice needle core biopsies were performed. Both were indefinite for diagnosis. The first report favoured a lipoma and the second report suggested the lesion represented oncocytic hyperplasia or an oncocytoma. The microscopic examination of the excised surgical specimen demonstrated typical features of oncocytic sialolipoma, characterized by a predominately lipomatous component, sparse normal-appearing salivary gland tissue and multiple oncocytic nodules. This is the second case of oncocytic sialolipoma reported to occur in the parotid gland.