Hidradenoma Papilliferum : Microscopic
Microscopic Features of Hidradenoma Papilliferum (continued): Cytologic atypia is absent or mild and the mitotic activity may be increased. Focal oxyphil metaplasia with increased cytologic atypia may be seen. Diastase-resistant PAS-positive cytoplasmic granules are frequently present. Some cases show prominent apocrine differentiation in the surface glandular cells. In the surrounding stroma, there may be residual anogenital mammary-like glands. Areas resembling sclerosing adenosis and ductal hyperplasia of breast may be seen. The presence of fibrosis may impart an infiltrative appearance to the glandular structures mimicking infiltrative carcinoma.