Lesions of uncertain malignant potential include radial scars, papillary lesions and mucoceles. Lobular neoplasia and atypical ductal hyperplasia (ADH) are often associated with such abnormalities and present similar problems. Columnar cell atypia and apocrine atypia, once their natural history has been elucidated, may join this group of lesions.

The management of lesions of uncertain malignant potential has become a more common and complex problem in recent years. The introduction of first core biopsy and then vacuum-assisted biopsy devices has led to an increase in the nonoperative diagnosis of such lesions. These lesions may be incidental findings that do not represent the clinical or radiological abnormality.

In the past, such lesions were managed by surgical excision (radial scar, papillary lesion and ADH) or by mammographic follow-up (lobular neoplasia). It is now recognised that the upgrade rates to ductal carcinoma in situ or invasive cancer vary in proportion to the degree of cellular atypia present and by the amount of tissue removed at percutaneous biopsy. Vacuum biopsy excision is also an option for some of these lesions.

In this session we shall discuss a number of such cases to highlight the difficulties and dilemmas found when managing these lesions.