Warthin-like mucoepidermoid carcinoma of the parotid gland: a clinicopathological analysis of two cases

Abstract

Mucoepidermoid carcinoma (MEC) is the most common malignant tumour of the salivary gland, primarily involving the parotid gland. Here, the cases of two patients, aged 47 and 67 years, respectively, who underwent surgery for pathologically confirmed Warthin-like MEC of the parotid gland between January 2019 and December 2019 in Anyang Tumour Hospital, are described. In each case, the tumour consisted of epithelial and lymphoid cell components, covered with two or more layers of epithelium, with visible scattered mucous cells, and lymphoid stroma with a large number of lymphocytes and germinal centres formed. Most importantly, the tumours lacked the well-organized, bilayered oncocytic epithelial structure that is characteristic of Warthin’s tumour. Mastermind like transcriptional coactivator 2 ( MAML2) gene rearrangements were identified in the tumour cells using break-apart fluorescence in situ hybridization (FISH) probes, confirming the diagnosis of Warthin-like MEC. Post-operatively, patients have remained disease free for 31 and 27 months, respectively. Warthin-like MEC of the parotid gland is rare and is often misdiagnosed as metaplastic Warthin’s tumour. Diagnosis depends mainly on the unique clinicopathologic features together with FISH analyses.

Warthin-like mucoepidermoid carcinoma of the parotid gland: Clinicopathological observation and literature review

“…Since the first report by Ishibashi et al 1 in 2015, only 28 cases ( Table 1 ) of WT-like MECs have been reported in the literature, including the present case. 1 , 2 , 5 – 7 , 11 , 12 , 14 – 18 The tumour preferentially affect females and all cases originate in the parotid gland. It is generally thought that this tumour appears in adults, but it may also occur in teenagers, as the broad age range is 13–67 years.…”