OSU Department of Pathology

Anatomical Pathology Interesting Case Conference

Microscopic Description:

Histology shows inflammatory cell infiltrates within the epididymal interstitium and irregular fascicles of smooth muscle are seen periductally and around vascular structures.

No evidence of cellular atypia, mitosis, necrosis or hemorrhage.

Discussion:

Smooth Muscle Hyperplasia of Epididymis is a rare benign painless scrotal tumor which can be coincidental or a subclinical finding in men between 45-80 years.

Grossly, the masses range in size from 6mm to 70mm (mean 26mm). Lesion may appear as discrete or ill-defined nodules, fusiform or cord-like masses, or diffuse thickening with enlargement of the paratesticular soft tissues.

Microscopically, ducts are surrounded by irregular fascicles of hyperplastic smooth muscle with no cellular atypia, mitosis or necrosis. The tubules in the epididymal tail have a prominent overgrowth of smooth muscle coat compared with those in the head causing possible obstruction of the epididymal or vas deferens ducts. Cystic spaces and ducts are lined by columnar epithelium containing spermatozoa.

The tumor is negative for markers of germ cell and sex cord-stromal differentiation.

Surgical excision serves both diagnostic and therapeutic purposes, with no reported cases of recurrence or disease progression.

References:

Alruwaii F, Grignon DJ, Idrees MT. Smooth muscle hyperplasia of the testicular adnexa: a clinicopathologic study of 12 cases. Hum Pathol. 2020 May;99:27-35. doi: 10.1016/j.humpath.2020.03.003.

 

Blach O, Pollock A, Douglas D. Smooth muscle hyperplasia of the epididymis. J Surg Case Rep. 2011 Oct 1;2011(10):10. doi: 10.1093/jscr/2011.10.10. PMID: 24950555.

Barton JH, Davis CJ Jr, Sesterhenn IA, Mostofi FK. Smooth muscle hyperplasia of the testicular adnexa clinically mimicking neoplasia: clinicopathologic study of sixteen cases. Am J Surg Pathol. 1999 Aug;23(8):903-9. doi: 10.1097/00000478-199908000-00007.

Lanzafame S, Leonardi R, Caltabiano R. Simultaneous leiomyoma and controlateral smooth muscle hyperplasia of the epididymis: a case report. Pathologica. 2009 Jun;101(3):119-22.

Shehabeldin A, Al Sannaa G, El-Zaateri Z, Andino L, Schmolze D, Chapman D, Ayala A, Ro JY. Leiomyoadenomatoid Tumor of Epididymis: A Variant of Adenomatoid Tumor. Ann Clin Lab Sci. 2020 Nov;50(6):813-817.

 

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