Inflammatory Skin Change From a Small 0.9 cm Primary Breast Cancer Not Seen on Initial Imaging: A Case Report

Most inflammatory breast cancers are caused by invasive ductal cell carcinomas that arise from mammary epithelial cells lining the breast ducts. Typically, in these cancers, radiological signs are conspicuous, and a diagnosis is made after standard mammographic imaging or ultrasound. We report the case of a 54-year-old female who presented to a mammography clinic with right-sided breast pain and swelling. Upon physical examination, there was no palpable mass. Ultrasound and mammogram findings included mild skin thickening, normal-sized but irregularly shaped axillary lymph nodes, and no breast mass. Due to the presence of inflammatory changes (skin thickening) and abnormal lymph nodes but no obvious mass, an MRI was done to find the primary mass after a core needle biopsy of one lymph node showed metastatic ductal disease. In this patient, a 0.9 cm mass was found at the right 8:00 position on MRI. A second-look ultrasound was then performed and the mass was identified, followed by an ultrasound-guided core biopsy. The biopsy showed an invasive ductal cell carcinoma. In most cases, inflammatory breast cancer is associated with larger tumor sizes. However, a subset of patients with inflammatory breast cancer may present with a small primary breast tumor that causes inflammatory changes. Here, we present a rare case of inflammatory breast cancer associated with a small breast mass measuring less than 1 cm in size.