vasitis nodosa vasitis nodosa vasitis nodosa is a complication experienced in approximately 66% of men who undergo vasectomy. it is a benign nodular thickening of the vas deferens, in which small offshoots proliferate, infiltrating surrounding tissue. it can be mistaken for low-grade adenocarcinoma by pathologists, and is implicated in late vasectomy failure. vasitis nodosamicrograph of vasitis nodosa (left of image). h&e stain.specialtyurology