Smooth Muscle Hyperplasia of Testicular Adnexa

The location of this lesion was epididymis. The smooth muscle fascicles are arranged concentrically in a periductal pattern. They may also show perivascular, interstitial, or mixed patterns. The etiology is unknown, although obstruction of vas deferens or epididymal ducts has been suggested as the cause. This is a benign non-neoplastic process with no clinical significance (other than it's mimicking a neoplasm clinically). No recurrences have been reported after excision.

Ref: Smooth Muscle Hyperplasia of the Testicular Adnexa Clinically Mimicking Neoplasia : Clinicopathologic Study of Sixteen Cases. Barton JH, Davis CJ, Sesherhann IA, Mostofi FK. Am J Surg Pathol 23(8):903-909, 1999.