Clear Cell Borderline Tumor : Microinvasion

Borderline clear cell adenofibroma with a 2mm focus of microinvasion in a 10 cm tumor. The remainder of the tumor was composed entirely of benign areas. Clear cytoplasm and cytologic atypia are evident in the small nests. The larger dilated glands are lined by flattened epithelium lacking atypia. Elsewhere, there was multilayering and pseudostratification with mild nuclear atypia. Mitotic activity was not increased.