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.

Keywords: Extensive lipomatous differentiation; fine-needle aspiration cytology; hard palate; minor salivary gland; pleomorphic adenoma.

Figure 1

Lesion manifested as a mass in hard palate

Figure 2

Epithelial/myoepithelial cells (a) and metachromatic stromal fragment (b) accompanying adipose component on FNA (Pap, ×40 and ×100). Adipose component involving more than 90% of the tumor, septa-forming epithelial/myoepithelial groups and chondromyxoid stroma (c,d), (H and E, ×40)