Pseudomalignant Changes in Benign Phylloides Tumor of the Breast

Overview

Phylloides tumor of the breast is well known entity in pathology for a long time. It includesfibroepithelial tumors of the different biological character. They are generally divided into threegroups: benign, low-grade malignant (borderline) and high-grade malignant. Adenoses of thebreast are a group of the benign lesions, the main feature of which is the proliferation of theglandular component of the breast. More frequent adenoses occurring in practice are: blunt ductadenosis, sclerosing adenosis, nodular adenosis, adenosis tumor and florid adenosis. The lessfrequent adenoses are: microglandular adenosis, tubular adenosis, apocrine adenosis, and myoepithelial(adenomyoepithelial) adenosis. In this article two histologically unusual lesions of thebreast in middle-aged women are presented, consisting of the benign variants of the phylloidestumor, modified distinctly by various types of adenoses, which can cause, together with intensivemyoepithelial proliferation, great diagnostic problems, especially on frozen sections. They may bemistaken with invasive ductal or lobular cancer. Reliable differentiation between these entities ispossible only by using of the immunohistochemical methods.

Key words:
benign phylloides tumor of the breast -⁠ adenosis of the breast -⁠ myoepithelial proliferation -⁠ invasive carcinoma -⁠ frozen section -⁠ immunohistochemistry