Usual hyperplasia, atypical hyperplasia and carcinoma-in-situ of breast: a morphologic study

Objective To study the morphologic classification of mammary ductal hyperplasia, and its criteria and the significance in distinguishing atypical hyperplasia from carcinoma-in-situ. Methods The clinicopathologic features of 300 cases of hyperplasia of breast were reviewed. Whole-organ HE sections were also available in 86 cases of breast carcinoma. The occurrence of atypical hyperplasia in adjacent breast tissue was assessed. Results Fibroadenomatoid changes were typically observed in the 21-30 age groups and atypical hyperplasia occurred more frequently in 40 - 60 age groups. Amongst the hyperplastic cases, cystic diseases of the breast were noted in only 6% . In contrast, fibroadenomatoid changes were more common (25.4%) . Atypical ductal hyperplasia occurred in adjacent breast tissue of 65. 1% of the carcinoma cases. The incidence was higher ( 74. 9% ) if the main lesion was ductal carcinoma-in-situ. Conclusions There is a close association between atypical hyperplasia and breast carcinoma. It is prudent to distinguish between usual and atypical hyperplasia. Morphologic differentiation between atypical ductal hyperplasia and ductal carcinoma-in-situ may sometimes be difficult.