Breast papillomas with atypical ductal hyperplasia: a clinicopathologic study

Breast papillomas with areas of atypical proliferation reminiscent of ductal carcinoma in situ (DCIS) and atypical ductal hyperplasia (ADH) are rare, but pose considerable diagnostic difficulty when encountered. The clinicopathologic features of 20 women 27 to 78 years of age with papillomas having atypical proliferations are reviewed. They presented with palpable masses or nipple discharge. Histologically, parts of all lesions had features of papillomas with a biphasic proliferation of benign epithelial cells and myoepithelial (ME) cells. Part of the lesion in each papilloma also had an expansile proliferation of larger uniform cells having evenly spaced, round nuclei and a solid to subtle cribriform growth pattern, similar to ADH or DCIS. These lesions tended to be large, complex or multiple. Twelve patients had 4 to 20 years of follow-up after biopsy only. One each had concurrent and previous contralateral breast carcinoma. Two developed invasive carcinoma of the contralateral breast in 15 and 18 years, respectively. Two developed DCIS on the same side in 2 and 8 years. Six had recurrent papillomas with (5) or without (1) ADH in 1 to 7 years all of whom had no further problems. Only 3 of 12 patients are event free. In contrast, only 8 recurrent papillomas, and 1 ipsilateral invasive carcinoma and 2 contralateral carcinomas occurred in 60 patients with papillomas without ADH in 4 to 18 years. Thus, the patients having ADH within papillomas seem to have greater likelihood of subsequent disease such as recurrences or overt neoplasia, but the length of follow-up and number of patients are not large enough to provide definitive answers. Because none of the patients developed invasive carcinoma on the same side, conservative management with close observation similar to that following a diagnosis of ADH seems to be appropriate.