Benign Myoepithelial Neoplasms of Salivary Glands: Clinicopathologic Profile and Literature Review

Abstract

OBJECTIVES

This article aims to expand the literature on myoepitheliomas by describing several cases with an emphasis on histological presentation, clinical appearance, and demographics. To the best of our knowledge, this article is the largest single-center case series of myoepitheliomas.

METHODS

A retrospective search for myoepithelioma salivary gland tumors in the oral and maxillofacial pathology archive at The Dental College of Georgia was performed. Patient demographics and the clinicopathologic features were collected and analyzed. Additionally, a comprehensive literature review of benign myoepithelioma of the salivary glands was conducted. The database PubMed was searched from (1/1/2008-to-9/1/2023) using the search terms: “salivary gland”, “myoepithelioma.” Demographic and clinicopathologic data were extracted and analyzed. Descriptive analysis was performed using SPSS Statistics Version 26 (IBM Corporation, NY). Categorical data was analyzed through the Fisher exact test. Results were considered statistically significant at (P < .05).

RESULTS

Institutional Case Series: The retrospective search revealed 13 cases of myoepithelial salivary gland tumors—9 benign myoepitheliomas & 4 malignant myoepithelial tumors (included for comparison). Tumor morphology was analyzed—epithelioid pattern, 6 cases (4 benign, 2 malignant); spindle cell pattern, 6 cases (4 benign, 2 malignant); plasmacytoid pattern, 7 cases (6 benign, 1 malignant). The characteristics of connective tissue trauma were also analyzed. The stroma was myxoid in 2 cases (1 benign, 1 malignant), fibrinous in 5 cases (4 benign, 1 malignant), and necrotic in 2 cases (2 malignant). The difference in reported clinicopathologic characteristics was not statistically significant, except for the presence of mitosis (p=.001).

CONCLUSIONS

Rare salivary gland tumors, especially those arising in atypical locations with ambiguous morphological patterns, present a unique diagnostic challenge. Due to myoepithelioma's ability to manifest in the various glandular structures of the head and neck, dental professionals and physicians who encounter head and neck pathology must recognize this entity as part of their differential diagnosis when clinically appropriate.

IMPLICATIONS

This project is targeted at clinicians and pathologists who encounter and manage head and neck pathology. Due to the rarity of this tumor class, there are many case reports, but no case series or reviews of this magnitude providing a clear profile of this neoplasm. The value of this article lies in the scope of our data set and the clinicopathologic overview it provides. It will contribute to improved differential diagnoses and, therefore, improved management of this condition.