Mucoepidermoid carcinoma of unknown primary in the head and neck - a case report and review of the literature

Sep 23, 2026

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Mucoepidermoid carcinoma of unknown primary (MEC-UP) in the head and neck presents as a rare form of the most common salivary gland cancer, with unknown-primary cancers generally carrying poorer outcomes. The report combines two low-grade patient cases from a tertiary center with a database search identifying five studies and seven MEC-UP cases, aiming to summarize diagnostic and management approaches. Findings emphasize PET-CT alongside panendoscopy and targeted biopsy, with consideration of diagnostic tonsillectomy. Primary surgical resection is recommended, with low thresholds for adjuvant radiotherapy to high-risk regions, especially in high-grade histopathology.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Abstract

Objective

Methods

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Introduction

Methods

Table 1. Summary of published cases of MEC-UP in the head and neck

[cambridge.org/jlo](cambridge.org/jlo) Clinical Records Phillip Staibano takes responsibility for the integrity of the content of the paper Cite this article: Chalmers K, Staibano P, Gupta MK, Au M. Mucoepidermoid carcinoma of unknown primary in the head and neck: a case report and review of the literature. JLaryngol Otol 2025; 139:521–525. [https://doi](https://doi). org/10.1017/S0022215124002147 Received: 19 July 2024 Accepted: 17 October 2024 First published online: 11 December 2024 Keywords: clinical management; mucoepidermoid carcinoma; head and neck cancer; unknown primary neoplasm Corresponding author: Phillip Staibano; Email: [staibapm@mcmaster.ca](staibapm@mcmaster.ca) © The Author(s), 2024 . Published by Cambridge University Press on behalf of J.L.O.(1984) LIMITED. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence ([http://](http://)[ ](http://)[creativecommons.org/licenses/by/4.0](creativecommons.org/licenses/by/4.0)), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited. Mucoepidermoid carcinoma of unknown primary in the head and neck: a case report and review of the literature Kieran Chalmers1 , 2 , Phillip Staibano1 ,3 , Michael K. Gupta1 and Michael Au1 1 Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, McMaster University, Hamilton, 2 ON, Canada; Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada and 3 Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada Abstract Objective. Mucoepidermoid carcinoma of unknown primary (MEC-UP) in the head and neck is a rare presentation of the most common salivary gland cancer. Cancers of unknown primary sites often have poorer prognoses than similar cancers with known primary. Few cases of MEC-UP have been reported; therefore, the objective of this report is an overview of the diagnosis and management of MEC-UP. Methods. We present two patients with low-grade MEC-UP at a high-volume tertiary care institution in Ontario, and a database search returning 1560 citations of which five studies with seven MEC-UP cases were identified. Results. Review of the limited cases suggest many clinicians use positron emission tomography-computed tomography (PET-CT) in addition to panendoscopy and targeted biopsies with consideration for diagnostic tonsillectomy in diagnostic work-up. Conclusion. Like other salivary gland cancers, primary therapeutic surgical resection is recommended with low threshold for adjuvant radiotherapy to regions at high risk for harbouring the primary malignancy, especially in cases of high-grade histopathology. Introduction Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy, characterized by a mixed histological pattern of epidermoid, mucous-producing and intermediate cells.1–3 While often found in the parotid glands, primary tumours can arise in any major or minor salivary glands.4 , 5 Prognosis in MEC is variable, with studies showing five-year survival rates between 87 and 98 per cent and 22 and 67 per cent in low-grade and high-grade tumours, respectively.6–9 Cancers of unknown primary (CUP) present as metastatic lesions without any known primary site despite investigative work-up.10 CUPs represent 3–5 per cent of all malignant epithelial tumours, carry a worse prognosis than their counterparts with known primary and can be aggressive with a poor response to empiric treatment.11–14 They are estimated to comprise around 5 per cent of head and neck cancers, with five-year overall survival rates reported around 30–40 per cent.15 Current literature detailing management of head and neck CUP is mostly in the context of squamous cell carcinoma, with little information on the management of MEC-UP available.16 , 17 Hence, MEC-UP presents a unique clinical challenge, with only a handf

FAQs

What is mucoepidermoid carcinoma of unknown primary (MEC-UP) in the head and neck?

MEC-UP refers to mucoepidermoid carcinoma that presents without an identifiable primary site in the head and neck, despite investigative work-up.

How were the cases and literature included in the study?

Two low-grade MEC-UP patients were presented, and a database search of Medline (Ovid) and Embase from inception to April 2024 identified 1560 unique citations, with five studies and seven MEC-UP cases included after screening and full-text review.

What diagnostic and treatment approaches are highlighted in the limited reviewed cases?

The review suggests clinicians use PET-CT in addition to panendoscopy and targeted biopsies, with consideration of diagnostic tonsillectomy during work-up. Primary therapeutic surgical resection is recommended, with a low threshold for adjuvant radiotherapy to high-risk regions, especially for high-grade histopathology.

Sep 23, 2026

Uploaded by Adam