Ectopic mammary gland tissue in the vulva is an uncommon clinical or pathologic finding. Such ectopic tissue can be the site of the same physiologic and pathologic processes found in the normal breast. However, the occurrence of adenocarcinoma is very rare, the first case being reported by Greene in 1935. We here report the 16th case of primary "breast-like" cancer arising in the vulva, together with a critical review of the literature, in order to highlight the dilemmas of a clinical approach to this neoplasm. Clear guidelines for diagnosis and therapy are still unavailable. The main diagnostic criteria suggested by the authors of previous reports are discussed together with our own findings. The therapeutic approach to this rare malignancy is also critically reviewed. In our opinion, when diagnosis of breast-like vulvar cancer is finally confirmed, treatment and follow-up should be the same as that would be chosen in a case of orthotopic breast neoplasm.