[Pseudolymphoma of the breast involving the periareolar area]

Pseudolymphomas are a group of lymphoproliferative disorders which are difficult to classify and diagnose. They can affect several anatomical sites and, among these, a mammary localisation is considered rather rare. Pseudolymphomas of the breast carry an excellent prognosis, and no case of malignant degeneration has ever been described. On the contrary, cutaneous pseudolymphomas, which are considered very low-grade lymphomas by some authors, are actually able to progress to overt cutaneous lymphomas in a minority of cases. The authors present three cases of periareolar pseudolymphoma of the breast. The first two were characterised by the presence of an elevated serum antibody titer to Borrelia, and were therefore diagnosed as lymphocytoma cutis, a disorder affecting 0.6-1.3% of patients with Lyme's disease. Both cases had a benign clinical course, as confirmed by the negative follow-up after more than three years. On the contrary, the third pseudolymphoma, classifiable as an idiopathic form, relapsed locally after ten years, thus testifying to the benign nature of the lesion, but also demonstrating that the lymphoproliferative process may still be active after a long period of time. The last case emphasizes the need for long-term follow-up of these patients.