Multiple bilateral breast adenomata in identical adolescent Negro twins.

Identical adolescent Negro twins presented with multiple bilateral breast adenomata. There were three pure tubular adenomata, one mixed tubular and fibroadenoma, four glandular fibroadenomata and one typical intracanalicular fibroadenoma. Tubular adenomata are exceedingly rare and this report adds a further three to the literature. Furthermore, the close similarity of the glandular fibroadenomata and tubular adenomata, the occurrence of tubular and fibroadenomatous areas in the same tumour, and the simultaneous occurrence of both tumour types in the same genetic setting, point to a close relationship between these types of neoplasm. The simultaneous occurrence of breast adenomata in identical twins suggests, but does not prove, an important genetic contribution to the aetiology of these tumours. The twins were both virgins, and, therefore, it is clear that pregnancy is not a pre-requisite for the development of tubular adenomata, as has been suggested.