Solid Papillary Carcinoma of the Breast With Invasion and Aggressive Characteristics: A Case Report

Solid papillary carcinoma (SPC) is a rare disease of the breast and usually shows favorable biology, with or without invasion. We experienced an SPC with invasion and aggressive biology, and report its characteristic image findings in this article. A 54-year-old woman with breast cancer, histologically diagnosed at another hospital, was admitted to our hospital for a left femoral neck fracture and underwent orthopedic surgery. During the admission, the patient requested that we operate on her breast cancer. Mammography showed a well-circumscribed mass with pleomorphic and linear calcifications, the latter not pointing toward the nipple. Ultrasound clarified many small cystic areas and multiple echogenic spots in the tumor. Magnetic resonance imaging of the mass showed low signal on T1-weighted images, weak high signal on fat-suppressed T2-weighted images, and a slow/plateau pattern on dynamic studies. Core needle biopsy pathologically led to the diagnosis of SPC with invasion. The patient, therefore, underwent a mastectomy and a sentinel node biopsy. Postoperative pathological study showed no lymph node metastasis but aggressive characteristics such as nuclear grade 3, estrogen receptor negativity, and an extremely high Ki-67 labelling index of 80%. The patient, unfortunately, developed skin flap necrosis, had sudden visual deterioration due to the worsening of diabetic retinopathy, and has been unable to receive postoperative adjuvant chemotherapy for more than 3 months. Diagnostic physicians should note that linear calcifications in the mass pointing toward non-nipple directions should be an important diagnostic clue for SPC of the breast. Diagnostic physicians should further note that many small cystic components in the mass are also important diagnostic image findings for SPC of the breast.