A Case of Fibroadenoma Phyllodes with Invasive Ductal Carcinoma and Adenomyoepithelioma

Abstract

A 47-year-old woman was found to have a 4-cm-diameter mass that was palpable at the outer area in the right breast. The mass has been present since adolescence and has shrunk slightly. Mammary gland echography revealed a lobulated multinodular mass, and the echo density of the tumor distal to the nipple was lower than that of other areas. Breast contrast-enhanced MRI revealed an early enhancement in the tumor distal to the nipple. Based on a needle biopsy, the patient was diagnosed with phyllodes tumor with low-grade ductal carcinoma in situ (DCIS). Since the tumor extended to the subareolar area, breast-concerving surgery with resection of the areola tissue directly above the tumor were performed. The pathological diagnosis was fibroadenoma phyllodes with invasive ductal carcinoma and adenomyoepithelioma. The intraductal components similar to a low-grade DCIS extended into the fissure of the phyllodes-like foliate structure and formed an infiltrated area, partly extending outside the tumor. The resected margins were negative. Postoperative whole-breast irradiation was also performed.

In this case, while the fibroadenoma changed over the long-term course, phyllodes-like foliate structure, epithelial cancerization, and myoepithelial proliferation were noted in the interstitium. This case provides an interesting insight on the histogenesis of fibroadenoma and phyllodes.