Carcinosarcoma EX Pleomorphic Adenoma of Parotid: An Unusual Entity, A Report of Two Cases with Brief Review of Literature

Abstract

Background: Carcinosarcoma of the parotid is a biphasic neoplasm composed of malignant epithelial and mesenchymal components. It is a rare malignancy with < 100 cases reported in literature. Case Details (Methods and Results)Case 1: A 58-year-old male, underwent total parotidectomy for longstanding preauricular swelling. Histomorphology revealed a biphasic neoplasm composed of carcinoma with plasmacytoid morphology and osteosarcoma in the background of pleomorphic adenoma. Carcinoma component was confirmed to be myoepithelial carcinoma by immunohistochemistry. The patient presented with local recurrence two months later.Case 2: A 32-year-old female with swelling in the left cheek for 6 months and suspected to be malignant on biopsy underwent radical parotidectomy. It showed a biphasic neoplasm consisting of duct carcinoma with comedo necrosis and undifferentiated pleomorphic sarcoma in the background of pleomorphic adenoma which was confirmed by immunohistochemistry.Carcinosarcoma can arise both de novo and from long standing pleomorphic adenoma. Most patients are aged between 50 -70 years. Case 2 presented in 3 rd decade. The carcinoma component in case 1 was myoepithelial carcinoma which is unusual as compared to duct carcinoma. Sarcoma components may be chondrosarcoma, rhabdomyosarcoma, osteosarcoma or undifferentiated pleomorphic sarcoma. Conclusion:Malignancy in pleomorphic adenoma should be diligently screened for true sarcoma component due to worse prognosis than carcinoma ex pleomorphic adenoma and also exclude sarcomatoid carcinoma.