Apocrine adenoma of the breast: diagnosis on large core needle biopsy.

Apocrine adenoma is a rare benign epithelial tumour of the breast that can radiologically present as a well-defined opacity. The clinical, radiological and pathological findings of apocrine adenoma of the breast in a 72-year-old woman are described. Histologically, the tumour is characterised by a circumscribed proliferation of metaplastic apocrine cells which may contain calcifications. Pathological assessment of the lesion is essential in making the diagnosis.