Diagnostic and Differential Considerations in Squamous Breast Lesions

 

Squamous metaplasia is allegedly a very rare finding in breast tissue that has been previously reported in association with ducts, sclerosing lesions, fibrocystic changes, fibroepithelial lesions, papilloma(s), and cysts. Notably, it is not uncommon to see squamous metaplasia of lobules and ducts at the site of prior biopsy or resections. Although squamous metaplasia is clinically irrelevant, care should be taken to rule out a malignant process, which can also show squamous cells. The differential diagnosis would include low-grade adenosquamous carcinoma, metaplastic squamous cell carcinoma, cutaneous squamous cell carcinoma, and metastases.

Originally published on May 1, 2025

Lecture Presenter

Jolanta Jedrzkiewicz, MD

Jolanta Jedrzkiewicz, MD

Assistant Professor (Clinical) of Pathology
University of Utah School of Medicine
Pathologist
ARUP Laboratories

Dr. Jolanta Jedrzkiewicz is a pathologist at ARUP Laboratories and an assistant professor (clinical) at the University of Utah. Dr. Jedrzkiewicz received her medical degree from Poznan University of Medical Sciences and then completed an anatomic and clinical pathology residency at the University of Utah. She then completed a surgical pathology fellowship at MD Anderson and a gastrointestinal pathology fellowship at Mount Sinai Hospital. Dr. Jedrzkiewicz is board certified, and her research interests include diseases of the gastrointestinal tract with special interest in tumors of the appendix.

Objectives

After this presentation, participants will be able to:

  • List the differential diagnosis for breast biopsy showing carcinoma with squamous differentiation
  • Discuss the differential diagnosis for benign appearing cysts with a squamous lining
  • Review clinical scenarios in which it is more likely to encounter squamous metaplasia
  • Describe diagnostic criteria of low-grade adenosquamous carcinoma

Sponsored by:

University of Utah School of Medicine, Department of Pathology, and ARUP Laboratories