Eight Cases of Encapsulated Papillary Carcinoma

Abstract

Encapsulated papillary carcinoma (EPC) is a rare malignant papillary lesion newly classified as IB by the World Health Organization in 2012. We report eight cases of EPC experienced at our hospital.

The median age of the patients was 66.5 years. The main complaint was mass in five cases. Mammography was category 3 or higher in all cases. Ultrasound revealed six cases of mixed mass and two cases of solid mass. Needle biopsies were performed in seven cases, all of which were malignant ; one case was cytologically malignant. Mastectomy and partial mastectomy were performed in four patients each. Pathological findings revealed invasion in four patients and six patients were hormone receptor-positive. All invasive cases were human epidermal growth factor receptor 2-negative, and Ki-67 was > 14% in three invasive cases. Partial resections were treated with radiation : five hormone receptor-positive patients were treated with endocrine therapy and one patient underwent chemotherapy. Patients with EPC reportedly have a tendency to be older ; however, three of our patients were in their 40s. The prognosis of invasive cases was better than those classified as invasive cancers.

Rapid growth and high proliferative activity was noted in patients with invasive EPC ; this suggests the need to carefully monitor the prognosis of such patients.