Invasive Ductal Carcinoma of the Breast With an Uncommon Widespread Thick Hyperechoic Pattern: A Case Report

A 77-year-old woman visited our hospital due to a palpable breast mass. Mammography only showed a focal asymmetric density. In addition to one normal-sized lymph node with a punctate hyperechoic pattern, ultrasound showed widespread, thick hyperechoic areas with indistinct margins and adjacent hypoechoic areas. The hypoechoic areas had both an irregular shape and focal internal punctate high echoes on grayscale ultrasound, as well as blood inflow on Doppler ultrasound. Magnetic resonance imaging (MRI) of the mass showed weak high signals on fat-suppressed T2-weighted images and slow initial enhancement followed by persistent enhancement on dynamic studies, highly suggesting the hyperechoic areas to have abundant fat components. Core needle biopsy pathologically showed cancer cells with fat invasion. The patient, therefore, underwent mastectomy and axillary dissection. Postoperative pathological study showed cancer cells spreading in 25-mm sizes in the fat tissue, with microvoids around cancer cell clusters, and two metastatic lymph nodes. Immunostaining of the tumor showed estrogen receptor positivity (Allred score 7), progesterone receptor negativity, human epidermal growth factor receptor type 2 equivocality (fluorescence in situ hybridization (FISH) negative), and a Ki-67 labeling index of 35%. The patient has been well on adjuvant endocrine therapy without any events for three years. A diagnostic physician should note that microvoids just around cancer cell clusters may make the internal echoes of the metastatic lymph node high, and widespread cancer infiltration into the fat tissue generates an uncommon, widespread, thick hyperechoic pattern.