A case of oncocytic lipoadenoma of the submandibular gland and its diagnostic cytology challenges

Abstract

Lipomatous tumors of the salivary gland in general are rare and oncocytic lipoadenomas are even much rarer. Most of the reported cases of oncocytic lipoadenoma were located in the parotid gland and to the best of our knowledge, only four cases reported to arise from the submandibular gland. The preoperative interpretation of the aspirates taken from these lesions can be difficult and challenging. We report a case of a 41 year old gentleman who presented with submandibular gland swelling. CT scan of the neck revealed an oval‐shape enhancing mass in the inferior aspect of the right submandibular gland measuring 19 × 12 mm. Fine needle aspiration biopsy (FNAB) showed hypocellular smears with few clusters of epithelial cells having oncocytic appearance. The cytologic findings were interpreted as “oncocytic lesion.” Submandibular gland excision was done. Histologically, a final diagnosis of oncocytic lipoadenoma was rendered. We present this rare entity to add to the few cases reported to date and to upsurge awareness during cytologic examination of oncocytic salivary gland lesions.

An extremely rare case of giant oncocytic adenolipoma of the parotid gland

“…Histologically, oncocytic adenolipoma consists of circumscribed biphasic tumor surrounded by a thin fibrous capsule in which the adipose tissue intermingles with the oncocytic part. The epithelial component is formed only by the oncocytes with no ductal or acinar component, which is usually seen in sialolipoma 3 . The differential diagnosis of oncocytic adenolipoma includes all other lesions containing oncocytes, such as oncocytoma, oncocytic carcinoma, Warthin's tumor, and oncocytic cystadenoma, as well as oncocytic variants of pleomorphic adenoma, myoepithelioma, mucoepidermoid carcinoma, and epithelial‐myoepithelial carcinoma 6,14,17 .…”

“…The epithelial component is formed only by the oncocytes with no ductal or acinar component, which is usually seen in sialolipoma. 3 The differential diagnosis of oncocytic adenolipoma includes all other lesions containing oncocytes, such as oncocytoma, oncocytic carcinoma, Warthin's tumor, and oncocytic cystadenoma, as well as oncocytic variants of pleomorphic adenoma, myoepithelioma, mucoepidermoid carcinoma, and epithelial-myoepithelial carcinoma. 6,14,17 The excisional surgery was done as suggested by previous literature.…”

“…2 It differs from the sialolipoma in which the epithelial part consists of normal looking serous acini. 3 Only the case reports are published in the literature due to its rarity. In the recent fourth edition 2017 World Health Organization (WHO) histologic classification of tumors of salivary glands, sialolipoma has been included, but oncocytic adenolipoma is still not included.…”

“…Oncocytic adenolipoma or lipoadenoma is one of the rare biphasic lipomatous tumors which is composed of oncocytes admixed with mature adipocytes 2 . It differs from the sialolipoma in which the epithelial part consists of normal looking serous acini 3 . Only the case reports are published in the literature due to its rarity.…”

Complex Component of Oncocytic and Non-Oncocytic Lipoadenomas in the Parotid Gland: A Case Report

“…Most oncocytic lipoadenomas have occurred in the parotid gland. They are benign tumors mainly composed of oncocytes with various fatty components [2][3][4][5][6]. We encountered a case of oncocytic lipoadenoma, whose histologic findings resembled salivary oncocytoma.…”