Multiple Small Axillary Masses With Haloes on Ultrasound Mimicking Lymph Node Metastases in Breast Cancer: A Case Report

A 66-year-old woman had presented with various oncological events, such as in-breast recurrence, local recurrence, contralateral axillary lymph node recurrence, left ductal carcinoma in situ (DCIS) of the breast, and primary unknown metastatic neuroendocrine tumor of the liver, after neoadjuvant chemotherapy followed by breast-conserving therapy with sentinel node biopsy (SNB) for right breast cancer, i.e., invasive micro papillary carcinoma. Attending surgeons had managed these events with salvage mastectomy and re-SNB, wide resection, axillary lymph node dissection, nipple-sparing mastectomy in a thick flap manner, and partial hepatectomy, respectively. Follow-up positron emission tomography/computed tomography further showed multiple fluorodeoxyglucose uptakes in the left axilla. Ultrasound showed multiple small lesions with internal low echoes, obscured margins, and haloes. Core needle biopsy pathologically showed atypical cells growing in a trabecular and solid fashion without any lymph node structures. Under the tentative diagnosis of in-breast recurrence of the left DCIS in the preserved thick flap, the patient underwent resection of the multiple axillary lesions. All nine lesions showed estrogen receptor-positive and human epidermal growth factor type 2 receptor-negative cancer cells with a very low Ki-67 labelling index of 2%, highly resembling the pathological findings of the left DCIS. These images and pathological findings suggest that multiple small axillary masses with haloes on ultrasound are not lymph node metastases of breast cancer. Breast specialists, therefore, should develop therapeutic strategies based on the idea that multiple small axillary nodules with haloes on ultrasound have a high probability of in-breast recurrence.