# Malignant adenomyoepithelioma of the breast with axillary metastasis: a case report in a patient undergoing EGFR-targeted therapy and literature review

## TL;DR

A rare breast tumor called malignant adenomyoepithelioma with axillary metastasis is reported in a patient undergoing lung cancer treatment.

## Contribution

This case report adds to the limited literature on axillary metastasis in malignant adenomyoepithelioma and highlights challenges in diagnosis and treatment.

## Key findings

- Malignant adenomyoepithelioma can persist for over 20 years and progress during EGFR-targeted therapy.
- Axillary lymph node metastasis is rare in this tumor and often undetected by preoperative imaging.
- Diagnosis relies on postoperative pathology and immunohistochemistry due to low imaging sensitivity.

## Abstract

Malignant Adenomyoepithelioma (MAME) is a very rare tumor derived from the mixed proliferation of glandular epithelium and muscular epithelium. It has a wide spectrum of histomorphology, a high risk of local recurrence and distant metastasis, and there are few reports of axillary lymph node metastasis. This article reports a case of a breast nodule that had persisted for over 20 years and progressively enlarged during targeted therapy for pulmonary adenocarcinoma. It was eventually diagnosed as malignant adenomyoepithelioma of the breast, and axillary lymph node metastasis was later found. The sensitivity of preoperative imaging is low, and the diagnosis relies on postoperative pathology and immunohistochemistry. The efficacy of adjuvant therapy (chemotherapy or radiotherapy) is uncertain and mostly based on individual experience. Therefore, this article, in combination with previous research, comprehensively analyzes the clinical and pathological characteristics, treatment methods, and prognosis of this disease to enhance the understanding of this tumor and optimize its management strategy.