Intraductal papilloma in an axillary lymph node of a patient with human immunodeficiency virus: a case report and review of the literature

INTRODUCTION Inclusions of ectopic breast tissue in axillary lymph nodes are reported very infrequently and typically are only identified microscopically as an incidental finding. Furthermore the development of a benign proliferative lesion in the form of an intraductal papilloma from intranodal ectopic breast tissue is an extremely rare phenomenon with only three previous cases reported. This report describes an unusual and rare case of an intraductal papilloma arising in an axillary lymph node of a patient known to have the human immunodeficiency virus. CASE PRESENTATION A 40-year-old Black African woman underwent excision of an enlarged palpable axillary lymph node. In the preceding 7 years she had received at least six separate surgical excisions to her ipsilateral breast for papillomatosis. The last surgical intervention was performed 1 year prior to presentation with an enlarged axillary lymph node. Histological examination of her axillary lymph node revealed a papillomatous proliferative epithelial lesion within an apparent encompassing duct, resembling a mammary intraductal papilloma. In the surrounding lymphoid tissue small groups of duct-like structures were additionally noted. Immunostaining with a panel of myoepithelial markers in conjunction with oestrogen receptor produced a mixed heterogeneous staining pattern in both the papillomatous lesion and the peripheral duct-like structures. This confirmed the diagnosis of a benign intraductal papilloma within an axillary lymph node, considered to have arisen from ectopic breast tissue. CONCLUSIONS This case demonstrates that intranodal ectopic breast tissue has the potential to undergo benign proliferative change albeit extremely rarely. Therefore this possibility must be considered to ensure the correct diagnosis is made. In addition, to the best of our knowledge, this is the first case report which has described recurrent intraductal papillomas and the subsequent development of an intraductal papilloma within an ipsilateral axillary lymph node, in a patient who is human immunodeficiency virus positive. There is minimal literature investigating the specific types of breast pathologies experienced by patients infected with human immunodeficiency virus and it remains unexplored as to whether human immunodeficiency virus may lead to proliferative papillomatous epithelial changes. This report considers the role of the human papillomavirus and recommends that further investigatory studies are required.