Paget's disease of the breast generally affects middle-aged and older
females. In the majority of cases, it is considered to be the result o
f epidermal spread from a contiguous mammary duct carcinoma. We report
the first case in an adolescent female with an accessory nipple. The
histomorphology and immunophenotypic findings support the hypothesis o
f in situ transformation and suggest a histologic spectrum exists in t
erms of cytologic atypia.