Needle core biopsy for the assessment of unilateral breast masses in men.

Although unilateral male breast swelling is relatively common, a histological diagnosis is infrequently obtained. From 1998 to 2003 we routinely performed needle core biopsy on all men presenting with unilateral breast swelling in whom there was diagnostic uncertainty. Of 113 patients, 93% had gynaecomastia, two patients had primary breast cancer and one had metastatic lymphoma.