Lipomatous pleomorphic adenoma in the hard palate: Report of a rare case with cyto-histo correlation and review

Abstract

Pleomorphic adenoma is the most common benign tumor of the salivary glands. They are usually composed of epithelial/myoepithelial cells and chondromyxoid stroma. Extensive lipomatous differentiation is very rare. We report a case of lipomatous pleomorphic adenoma (LPA) that presented with a mass in the hard palate of a 32-year-old woman. The fine-needle aspiration cytology material was reported as benign cytology consistent with adenoma with major adipocytic component. Histopathological examination of the excision material displayed that more than 90% of the tumor was adipocytic in texture, containing scant epithelial and myoepithelial cells and chondromyxoid stromal fragments. Preoperative cytodiagnosis of lipomatous pleomorphic adenoma on FNA is based on cytomorphology intimately associated pleomorphic adenomatous and lipomatous tissue elements. LPA should be on the mental list of the (cyto)pathologist in differential diagnosis of lipomatous tumors or non-tumorous lipomatosis or carcinoma invasion in the adipose tissue of the minor salivary gland of the hard palate.

An Unusual Variant of a Common Palatal Salivary Gland Tumor: Case Report of a Pleomorphic Adenoma with Significant Lipomatous Metaplasia

“…Since the lipomatous pleomorphic adenoma is a fairly rare neoplasm, there were no reports of recurrence or malignant transformation in any of the reported LPA cases [4]. The patient in our report has also been free of any recurrence or malignant transformation to date.…”

“…The stromal element demonstrates varying degrees of myxoid, hyaline, cartilaginous, or osseous differentiation [3]. A lipomatous component may also be seen but prominent lipomatous differentiation is a rare variation of pleomorphic adenoma [4].…”

“…Only a few cases of lipomatous pleomorphic adenomas and pleomorphic adenomas with extensive lipomatous metaplasia have been reported and well documented in the English literature [4–9]. Table 1 identifies these cases along with their attributes.…”

Pleomorphic adenoma with lipometaplasia: Rare histology finding of a common entity

“…Ng et al (1995) first reported case of PA with extensive lipometaplasia in submandibular glands. 2,3 Seifert et al defined lipomatous PA as pleomorphic adenoma with more than 90% lipomatous component of total tumour. 4 Haskel et al suggested myoepithelial origin for lipometaplasia as they have ability to transform into various metaplasia.…”

Lipomatous mixed tumor of the skin with cystic formation affecting the upper lip: A case report

“…MTS shares some features with pleomorphic adenoma of the salivary gland (1,9). To the best of our knowledge, 16 cases of pleomorphic adenoma with predominant adipocytes in the salivary gland has been reported, and the proportion of the tumor that was occupied by adipose tissue ranged from 25% to more than 95% (19)(20)(21). Thus a prominent adipocytic metaplastic pattern is rare in both MTS and pleomorphic adenoma.…”