Metaplastic carcinoma of breast: A series of nine cases from a regional cancer center in Northeast India

Background: Metaplastic carcinoma of the breast (MCB) is a rare histological subtype of breast carcinoma containing glandular and nonglandular components with mixed epithelial and mesenchymal differentiations. Aim of the Study: The study aimed to report clinical, radiological and pathological profiles, treatment and outcome of patients diagnosed with MCB from a tertiary care institute along with literature review. Materials and Methods: Diagnosed cases of MCB were obtained from the record over a period of January 2010 to December 2017, and data were recorded in a structured pro forma. Results: A total of 9 (0.9%) cases of MCB were identified out of 1031 breast cancer patients with the median age of presentation of 53 years. The palpable lump was the most common presentation (77.78%). The mean tumor size was 4.9 cm in greatest dimension. Sonographically, most of the lesions were solid (44.44%) followed by cystic (33.33%). Mammographically, microcalcifications were absent in eight cases. Histologically, 55.56% of cases were purely epithelial subtype (3: pure squamous and 2: adenosquamous) and 4 (44.44%) cases were mixed epithelial and mesenchymal subtypes (3: carcinosarcoma and 1: invasive lobular carcinoma with sarcomatous component and osseous metaplasia). All the cases were having triple-negative receptor status. Modified radical mastectomy (MRM) was performed in all cases and 33.33% of cases had axillary node positive. About 77.88% and 88.89% of cases received adjuvant chemotherapy and adjuvant radiotherapy, respectively. At median follow-up of 27 months, local recurrence and distant metastases were seen in 1 and 3 cases, respectively. At present, 33.33%, 22.22%, and 44.45% of patients were died, alive, and lost for follow-up, respectively. Conclusion: MCB is a rare histologic subtype of breast cancer with larger tumor size at presentation and MRM is the preferred surgical procedure over breast conservation surgery. Long-term and regular follow-up is necessary to know the outcome.