# Parotid Gland Mass as the First Manifestation of Recurrent Metastatic Breast Carcinoma: Diagnostic Pitfalls and Therapeutic Considerations in Oral-Maxillofacial Care

## TL;DR

A woman with a history of breast cancer developed a parotid gland mass, which was later diagnosed as metastatic breast cancer, highlighting the need for careful evaluation in similar cases.

## Contribution

This case report highlights the diagnostic challenges of metastatic breast cancer presenting as a parotid gland mass and emphasizes the importance of considering metastasis in differential diagnoses.

## Key findings

- Metastatic breast carcinoma was confirmed in the parotid gland via histopathological and immunohistochemical analysis.
- The patient's parotid mass was initially misinterpreted as non-metastatic despite her history of breast cancer.
- The patient later developed pulmonary metastases and died, underscoring the aggressive nature of this rare condition.

## Abstract

Breast cancer metastasis to the parotid gland is extremely rare and can easily be misinterpreted as a primary salivary gland tumor. In this report, we describe a 60-year-old woman who developed a parotid mass 18 months after completing breast cancer treatment. Despite her oncologic history, the initial clinical and imaging findings were inconclusive. Comprehensive evaluation including CT, PET-CT, and histopathological analysis confirmed metastatic breast carcinoma infiltrating the parotid gland. This case underscores the importance of considering metastatic disease in the differential diagnosis of parotid masses, particularly in patients with a prior history of breast carcinoma, to ensure timely recognition, accurate diagnosis, and appropriate multidisciplinary management.

Breast cancer rarely metastasizes to the parotid gland. Early recognition in patients with a history of malignancy is critical for timely diagnosis and treatment. We report the case of a 60-year-old female who presented with a two-month history of a left periauricular mass, 18 months after completing treatment for breast carcinoma. Despite the patient’s oncologic history, initial evaluation by our maxillofacial surgery service showed no evidence of distant metastasis, and we initially ruled out metastatic disease. Clinical evaluation, contrast-enhanced computed tomography (CT), fine-needle aspiration cytology (FNAC), PET-CT, and histopathological analysis were performed. Given the persistent and progressive nature of the mass, surgical excision was undertaken to obtain a definitive diagnosis and provide local control. Immunohistochemical analysis of the resected mass and adjacent node confirmed metastatic breast carcinoma infiltrating the parotid parenchyma and an intra-parotid lymph node, with strong positivity for progesterone receptor (PR) and carcinoembryonic antigen (CEA). Unfortunately, several months later, the patient developed pulmonary metastases and subsequently died.