[Synchronous and ipsilateral invasive ductal carcinoma of the breast occurring near a phyllodes tumor - a case report].

We report 2 cases of invasive ductal carcinoma of the breast occurring near a phyllodes tumor. The first case was ofa 58- year-old woman who had a tumor in her right breast and visited our hospital. Following a core needle biopsy (CNB), a malignant phyllodes tumor was diagnosed. We performed a lumpectomy for the phyllodes tumor, with 1.5-cm surgical margins. Pathological diagnosis of the resected specimen confirmed the malignant phyllodes tumor. A ductal carcinoma in situ (DCIS) was also discovered near the phyllodes tumor. The second case was of another 58-year-old woman who had a big tumor in her right breast and visited our hospital. CNB resulted in pathological diagnosis ofa benign phyllodes tumor. The tumor was removed by a lumpectomy with 1.5-cm surgical margins. The pathological diagnosis from the resected specimen was borderline phyllodes tumor with invasive ductal carcinoma in the proximity. In both cases, DCIS could not have been diagnosed preoperatively.