Metaplastic Breast Carcinoma: A Case Report

Abstract

INTRODUCTION: Metaplastic breast carcinoma is a rare condition, representing less than 1% of the invasive carcinomas of the breast. These tumors, in addition to the carcinomatous component, are constituted by mesenchymal, fusocellular and squamous dominant elements. They are characterized by a high growth rate, aggression and immunohistochemical characteristics of the basal-like carcinomas of the breast (triple negative). REPORT: An eighty six years old lady, first seen at September 2011, at the Breast Surgery Department at Hospital das Clinicas, Universidade Federal de Minas Gerais, Brazil. She had a complaint of a palpable mass at her right breast. On her physical exam there was palpable mass of 5 cm at her right breast, extending to the axilla, consistent of a clinical staging of T4bN0M0. Her mammogram showed a spiculated nodule in axillary tail of Spence at the right breast, BIRADSTM 5. Her breast ultrasound showed a spiculated hypoechoic nodule of 3. 6 cm at the outer quadrant of her right breast, BIRADSTM 5. Incisional biopsy was performed, positive for a spindle cell neoplasm with a low mitotic index - this could represent a mesenchymal (fibrosarcoma) or mammary neoplasm (myofibroblastoma or spindle cell metaplastic carcinoma). Immunohistochemistry was positive for a metaplastic spindle cell carcinoma. Family at first did not allow the surgical procedure, which delayed her treatment. When authorized by the family, surgery was performed in March 2012 and she underwent a radical modified mastectomy. Her pathological findings were: metaplastic breast carcinoma type fibrosarcoma with mild cell pleomorphism, low histological grade, skin infiltrated by contiguity and free surgical margins. pT3(5, 5)N0(0/10)M0. New immunohistochemistry was performed at the surgical specimen compatible with a metaplastic spindle cell carcinoma (staining strongly positive for AE1/AE3, 34 beta E12 and p60). In July 2012, the patient was asymptomatic with no signs of local or systemic recurrence. She is regularly followed by the breast surgeons and clinical oncologists. DISCUSSION: Metaplastic breast carcinoma is associated with a faster local growth and a worse prognosis compared to ductal carcinomas. These metaplastic tumors show, in general, negative hormone receptors and Her2 negative on immunohistochemistry. In contrast, immunohistochemistry is often crucial in differentiating metaplastic carcinoma and primary sarcomas of the breast. The correct diagnosis of metaplastic carcinoma, differential diagnosis of sarcomas and invasive ductal carcinoma is important for proper treatment and prognosis. In relation to the metastatic potential, metaplastic tumors have higher rates of hematogenous metastases and lower rates of lymph node metastasis. There are no conclusive studies about the benefit of adjuvant chemo and radiation therapy, which makes surgery the main treatment.