Low grade mucoepidermoid carcinoma in a setting of Warthin′s tumor

Abstract

Warthin's tumor also known as papillary cystadenoma lymphomatosum is a common benign salivary gland neoplasm that occurs exclusively in parotid gland. Rarely, the tumor can undergo carcinomatous or lymphomatous transformation of epithelial or lymphoid component, respectively. Herein, we describe a case of 55-year-old female who had undergone parotidectomy for a rapidly growing tumor in the right parotid gland. The case was diagnosed as mucoepidermoid carcinoma developed in a setting of Warthin's tumor based on the histomorphology, special staining characters, and immunohistochemical findings. The pathogenesis and differential diagnoses of such rare malignancy has been discussed briefly.

Mucoepidermoid carcinoma arising in Warthin’s tumor of the parotid gland: Clinicopathological characteristics and immunophenotypes

“…Malignant transformation of Warthin’s tumor is more common in the lymphoid component than the epithelial component, although malignant carcinoma is very rare (0.3%) 8 . Carcinomatous components have been reported as mucoepidermoid carcinoma (MEC) 9 10 11 12 13 , squamous cell carcinoma (the most common) 8 14 , oncocytic carcinoma, adenocarcinoma 15 16 17 18 and undifferentiated carcinoma 19 20 .…”

Letter to the Editor Mucoepidermoid carcinoma in Warthin tumor of the parotid gland

“…5% of cases [ 1 ]. Warthin tumor affects mainly males in the 6 th and 7 th decade [ 1 , 3 , 7 , 8 ]. Recently, an increasing incidence for females has been reported [ 9 ].…”

“…Malignant transformation of WT is quite common in the case of the lymphoid component, while malignant carcinoma is a rare entity (0.3% cases) [ 7 , 16 ] and was first reported by Ruebner and Bramhall in 1960 [ 17 ]. Carcinomatous components can be represented by squamous cell carcinoma (the most common) [ 18 – 20 ], oncocytic carcinoma, adenocarcinoma, undifferentiated carcinoma and mucoepidermoid carcinoma (MEC) [ 21 – 25 ].…”

“…According to Mohapatra et al ., epithelial neoplastic tissue can appear in WT under the following types: 1) co-existing separate neoplasm, e.g. pleomorphic adenoma – the most common type; 2) metastatic tissue of another head and neck carcinoma; 3) primary carcinoma arising in the epithelial component [ 30 ].…”

“…In order to diagnose the latter, it is essential to find the bulk of the carcinoma inside the WT, and the oncocytic epithelium should contain transitional zones from a hyperplastic/dysplastic state to malignancy. The metaplasia alteration can be the result of inflammation or infarction [ 30 ]. Similar findings were presented by Yamada et al .…”