MAML2 rearrangement as a useful diagnostic marker discriminating between Warthin tumour and Warthin-like mucoepidermoid carcinoma

Michał Bieńkowski,Wojciech Biernat,Alina Kuźniacka,Mariola Iliszko,Michał Studniarek,Michał Kunc

doi:10.1007/s00428-020-02798-5

Michał Bieńkowski, Wojciech Biernat + Show 4 more

Open Access

https://doi.org/10.1007/s00428-020-02798-5

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Journal: Virchows Archiv	Publication Date: Mar 28, 2020
Citations: 16	License type: open-access

Affiliation: Gdańsk Medical University

Abstract

Warthin tumour is the second most common benign neoplasm of salivary glands. Despite its relatively characteristic histology, it may sometimes mimic other lesions. Here, we report two female non-smoker patients diagnosed with low-grade mucoepidermoid carcinoma with oncocytic epithelium and prominent lymphoid (Warthin-like) stroma and with molecularly confirmed MAML2 rearrangement. In addition, we screened a consecutive series of 114 Warthin tumour cases by means of MAML2 break apart fluorescence in situ hybridization to assess its value in differential diagnosis. MAML2 rearrangement was detected in both mucoepidermoid carcinoma cases, while all Warthin tumours were negative. Taking into account the literature data, Warthin-like mucoepidermoid carcinomas are more frequently observed in women, while a slight male predominance and smoking history are typical for Warthin tumour. In addition, the patients with Warthin-like mucoepidermoid carcinoma were significantly younger than those with Warthin tumour. To conclude, Warthin-like mucoepidermoid carcinoma may usually be suspected based on histology, while the diagnosis can be confirmed by means of molecular assays such as FISH. The investigation of MAML2 status is particularly advised when Warthin tumour is considered in a young, non-smoking, female patient.

Highlights

Warthin tumour (WT) is the second most common benign neoplasm of salivary glands
Warthin-like mucoepidermoid carcinoma (MEC) were more frequently observed in women (18/22 reported cases), while a slight male predominance is indicated for WT (p = 0.003 when compared to our group of WT; p < 0.001 when compared to group reported by Eveson et al [1, 35])
There is a crucial difference between WT and MEC

Summary

Introduction

Warthin tumour (WT) is the second most common benign neoplasm of salivary glands. It usually arises as a slow-growing, painless mass in the parotid of male smokers [1]. 5 were described as having Warthin-like histology (all such cases reported to date are summarized in Table 1 [8,9,10,11,12,13,14]) and harboured a mastermindlike transcriptional coactivator 2 (MAML2) rearrangement. This alteration occurs in > 50% of MECs and correlates with low-/intermediate-grade histology and a better prognosis [15].

30 NI 29 15 20 20 25 14 40 40 25 NI 31 32 33 NI 12 25 12 16 9 16

Materials and methods

Literature search

Discussion

Findings

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