Smooth muscle hyperplasia of the testicular adnexa clinically mimicking neoplasia - Clinicopathologic study of sixteen cases

Sixteen cases of a largely unrecognized benign cause for an intrascrotal ma ss are reported herein. These cases represent a nonneoplastic excess of nat ive smooth muscle in the paratestis or spermatic cord growing between or ar ound vessels or efferent ducts. The patients ranged in age from 46 to 81 ye ars, with a mean age of 63 years. The size, available in 10 of the cases, r anged from 6 mm to 7 cm, with a mean of 2.5 cm; there was no side predilect ion. Microscopically, the lesions consisted of fascicles of smooth muscle, growing in a periductal, perivascular, interstitial, or mixed pattern. The cohesive, interlacing growth pattern of a leiomyoma was missing in all case s. The cause of this lesion is not apparent, although microscopic epididyma l or vas deferens duct ectasia in some cases suggests a possible obstructiv e etiology. In any case, these are benign and without clinical significance after excision and correct diagnosis. Follow-up was available in 13 patien ts with no recurrences observed from 1 month to 16 years postoperatively.