A Case of Low-grade Adenosquamous Carcinoma of the Breast

Abstract

A 56-year-old woman was diagnosed with a right breast mass in a medical examination. Mammography revealed an elliptical, fine serrated, marginal, and highly dense tumor in the right breast U/O. Ultrasound revealed a well-demarcated low echoic mass with heterogeneity. Needle biopsy showed spindle-shaped cells with atypia and solid alveolar, cord-like, and sheet-like structures with dense proliferation and infiltration that suggested metaplastic carcinoma or reactive lesions. As the possibility of malignancy could not be ruled out, right partial mastectomy and sentinel lymph node biopsy was performed. Postoperative pathological findings showed low-grade adenosquamous carcinoma (LGASC) with atypical cells with prominent nucleoli proliferating invasively and a mixture of stratified squamous epithelium-like and ductal structures. LGASC is a rare disease with a frequency of 0.5-1%. The diagnostic criteria of LGASC for images and pathological findings have not yet been established. Therefore, this report will be beneficial for diagnosing future cases.