Do columnar cell lesions exist in the male breast?

Aims In females, columnar cell lesions (CCLs) have been recognized as putative precursor lesions of low-grade breast cancer, but their role in male breast carcinogenesis is as yet unclear. Methods and results We reviewed surgical resections from males with breast cancer (n=89), gynaecomastia (n=20) and normal breast specimens from autopsies (n=5) for the presence of CCL. In addition, we performed immunohistochemistry for cytokeratin 5/6 (CK5/6), CK14 and oestrogen receptor alpha (ER). In 19 of 89 resections (two DCIS cases and 17 invasive carcinoma), some individual ducts were found to contain cells with snouts on the luminal border but lacking further typical columnar cell lesion features. We mainly found three-layered ductal epithelium, characteristic for gynaecomastia and confirmed by immunohistochemistry. Moreover, we found a few ducts in male breast cancer sections that were clonally negative for basal cytokeratins. Conclusion We found no lesions with convincing CCL morphology at the periphery of invasive male breast cancers, in gynaecomastia or in normal male breast specimens. Although we cannot completely exclude the existence of CCLs in the male breast, these lesions seem to be very uncommon and are therefore unlikely to play a major role in male breast carcinogenesis.