Clinical, pathological, and molecular-genetic features as well as etiology of cutaneous pseudolymphoma (CPL, cutaneous lymphoid hyperplasia, lymphocytoma cutis) of the breast nipple are summarized. CPL presents as a nipple induration and it is often suspected to be Paget carcinoma pre-operatively. Histologically, atypical microscopic features of a dense lymhoid infiltrate with follicles often mislead to the diagnosis of a malignant lymphoma. However, CPL runs a benign course. Rare cases of CPL contain a clonal lymphoid population. A substantial number of CPL in the breast nipple is caused by antigenic stimulation by Borrelia burgdorferi. In some patients a tick bite is documented. CPL of the breast is commonly treated by excision, but some patients may be cured by antibiotic therapy. The presence of Borrelia burgdorferi should be detected using methods of serology, culture, and molecular biology. Beside CPL, the differential diagnosis of the breast nipple lesions further includes Paget carcinoma, eczema, and florid papillomatosis.

        Key words: breast – nipple – pseudolymphoma – skin lymphoid hyperplasia – lymphocytoma cutis – Borrelia burgdorferi