Nerve invasion by benign proliferating ductules in vasitis nodosa.

Vasitis nodosa is a benign reactive condition characterized by nodular thickening of the vas deferens which usually develops following vasectomy. In addition to chronic inflammation, fibrosis and sperm granulomas, an exuberant proliferation of ductules resembling invasive adenocarcinoma is seen. A review of vasa deferentia from 210 patients submitted to the surgical pathology service at Arizona Health Sciences Center yielded ten cases of vasitis nodosa. In two of these cases ductular epithelium was found within the endoneurium of small nerve fascicles. Two additional cases were referred to us, one of these showing ductular epithelium around a small peripheral nerve. The aggressive and infiltrative nature of the proliferating ductules in this relatively common benign lesion is important to recognize. Since nerve involvement has also been reported in fibrocystic disease of the breast, normal and hyperplastic prostate, and normal pancreas, it cannot be used as evidence for malignancy in these situations.