[Papillary cystadenoma: a rare differential diagnosis of a paratesticular tumour].

Testicular and paratesticular cystadenomas arise from an oviduct-like structure, which, morphologically, is almost identical with the ovarian surface epithelium. These are very rare benign tumours of adults. They present as asymptomatic cystic lesions. Bilateral paratesticular cystadenomas are associated with the Von-Hippel-Lindau syndrome and may be associated with infertility. Most cystadenomas are benign, but a few cases of malignant transformation of embryonic remnants have been reported in the appendix testis, including cases of adenocarcinoma, cystadenocarcinoma, and a Müllerian-type epithelial tumour with a low malignant potential. We report the case of a 74-year-old man with a rare paratesticular cystadenoma of the male adnexa.