Solitary pancreatic metastasis from breast matrix-producing carcinoma: A first case report

Abstract

Introduction: Breast matrix-producing carcinoma (MPC) is a rare histologic type. Pancreatic metastases from breast cancers are also rare. We report the first case of solitary pancreatic metastasis from breast MPC, treated with distal pancreatectomy. Case presentation: A 56-year-old woman presented with a 56-mm mass in her right breast and a swollen right axillary lymph node. Both lesions had characteristic early ring enhancement on dynamic magnetic resonance imaging (MRI). Tumor biopsy revealed MPC. She underwent total mastectomy and axillary clearance. On histopathologic examination, the tumor was composed of extracellular matrix with areas of osseous and chondroid differentiation without spindle cells or osteoclasts, surrounded by a dense population of glandular epithelial tumor cells. On immunohistochemical analysis, the tumor cells were positive for AE1/AE3 and cytokeratin 5/6. The final diagnosis was breast MPC with axillary metastasis. Two years later, dynamic MRI displayed a mass in the pancreatic body with early ring enhancement, suspicious for solitary breast MPC metastasis. Distal pancreatectomy was performed. Histopathologic examination revealed bone and cartilaginous matrix with necrosis, surrounded by pleomorphic sarcomatous tumor cells. Tumor cells showed less cytokeratin positivity than the primary breast lesion. These findings were compatible with breast MPC metastasis. Conclusion: Solitary pancreatic metastasis from breast MPC has not yet been reported. Surgical resection of malignant pancreatic metastases is controversial; however, considering that breast MPC has limited responsiveness to radiotherapy and chemotherapy, curative resection would be important in this case. The histopathologic features of MPC may reflect enhancement and calcification on radiologic studies.