High-grade HER2-positive mucoepidermoid carcinoma of the breast: a case report and review of the literature

Mario Della Mura; Céline Clement; Maria P Foschini; Sara Vander Borght; Lise Waumans; Peter Van Eyken; Esther Hauben; Machteld Keupers; Caroline Weltens; Ann Smeets; Ines Nevelsteen; Giuseppe Floris

doi:10.1186/s13256-023-04233-0

High-grade HER2-positive mucoepidermoid carcinoma of the breast: a case report and review of the literature

J Med Case Rep. 2023 Dec 8;17(1):527. doi: 10.1186/s13256-023-04233-0.

Authors

Mario Della Mura^#^{1

2

3}, Céline Clement^#^{4

5}, Maria P Foschini⁶, Sara Vander Borght^{1

2}, Lise Waumans⁷, Peter Van Eyken⁷, Esther Hauben^{1

2}, Machteld Keupers⁸, Caroline Weltens^{4

9}, Ann Smeets^{4

5}, Ines Nevelsteen^{4

5}, Giuseppe Floris^{10

11}

Affiliations

¹ Department of Imaging and Pathology, Laboratory of Translational Cell & Tissue Research, KU Leuven-University of Leuven, 3000, Louvain, Belgium.
² Department of Pathology, KU Leuven-University of Leuven, University Hospitals Leuven, Herestraat 49, Campus Gasthuisberg, 3000, Louvain, Belgium.
³ School of Medicine and Surgery, Magna Græcia University of Catanzaro, Viale Europa, Germaneto University Campus, 88100, Catanzaro, Italy.
⁴ Department of Oncology, KU Leuven-University of Leuven, 3000, Louvain, Belgium.
⁵ Department of Surgical Oncology, KU Leuven-University of Leuven, University Hospitals Leuven, 3000, Louvain, Belgium.
⁶ Department of Biomedical and Neuromotor Sciences, Unit of Anatomic Pathology, University of Bologna, Bellaria Hospital, 40139, Bologna, Italy.
⁷ Department of Pathology, Regional Hospital East Limburg (ZOL), 3600, Genk, Belgium.
⁸ Department of Radiology, KU Leuven-University of Leuven, University Hospitals Leuven, 3000, Louvain, Belgium.
⁹ Department of Radiotherapy Oncology, KU Leuven-University of Leuven, University Hospitals Leuven, 3000, Louvain, Belgium.
¹⁰ Department of Imaging and Pathology, Laboratory of Translational Cell & Tissue Research, KU Leuven-University of Leuven, 3000, Louvain, Belgium. giuseppe.floris@uzleuven.be.
¹¹ Department of Pathology, KU Leuven-University of Leuven, University Hospitals Leuven, Herestraat 49, Campus Gasthuisberg, 3000, Louvain, Belgium. giuseppe.floris@uzleuven.be.

^# Contributed equally.

Abstract

Background: Mucoepidermoid carcinoma of the breast is a rare special type of salivary gland-like tumor of the breast, usually displaying triple-negative phenotype. To date, only 64 cases have been reported in the English literature. Herein, we report the first case of mucoepidermoid carcinoma of the breast with human epidermal growth factor receptor 2 gene amplification.

Case presentation: A 58-year-old Caucasian woman treated with breast-conserving surgery, radiotherapy, and chemotherapy for an invasive breast carcinoma of no special type, relapsed 20 years later in the ipsilateral left breast. Histological examination of the core needle biopsy of the relapse deferred to the surgical specimen for the definitive diagnosis, because of the broad differential diagnosis. On the resected specimen we observed the presence of a poorly differentiated carcinoma with mucoepidermoid carcinoma of the breast typical features consisting of epidermoid, intermediate and mucinous cells lacking true keratinization, in keeping with the latest World Health Organization diagnostic criteria. The mucoepidermoid carcinoma of the breast was weakly estrogen receptor and androgen receptor positive and progesterone receptor negative, but exceptionally showed human epidermal growth factor receptor 2 gene amplification. Mastermind-like transcriptional coactivator 2 gene translocations were not detected by fluorescent in situ hybridization. The patient received adjuvant chemotherapy with anti-human epidermal growth factor receptor 2 therapy but no endocrine therapy. After 61 months of follow-up, no signs of local or distant recurrence were observed.

Conclusions: Mucoepidermoid carcinoma of the breast is a very rare entity. Despite being most frequently triple negative, the standard evaluation of receptor status is mandatory, as well as strict application of World Health Organization diagnostic criteria for correct patient management.

Keywords: Case report; HER2; Mucoepidermoid carcinoma of the breast; Salivary gland-like tumors of the breast; Triple-negative breast cancer.

Publication types

Case Reports
Review

MeSH terms

Breast Neoplasms* / diagnosis
Breast Neoplasms* / genetics
Breast Neoplasms* / therapy
Carcinoma, Mucoepidermoid* / diagnosis
Carcinoma, Mucoepidermoid* / genetics
Carcinoma, Mucoepidermoid* / pathology
Female
Humans
In Situ Hybridization, Fluorescence
Middle Aged
Neoplasm Recurrence, Local / pathology
Salivary Glands / pathology