Testis & paratestis
Nonneoplastic lesions
Smooth muscle hyperplasia
Author: Swapnil U. Rane, M.D.
Last author update: 1 September 2014
Last staff update: 26 January 2021
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Smooth muscle hyperplasia [title]
Table of Contents
Definition / general | Epidemiology | Sites | Etiology & Pathophysiology | Clinical features | Diagnosis | Laboratory | Radiology description | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Immunohistochemistry & special stains | Differential diagnosisCite this page: Rane SU. Smooth muscle hyperplasia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testissmoothmuscle.html. Accessed April 16th, 2024.
Definition / general
- Benign nonneoplastic smooth muscle hyperplasia involving testicular adnexa around vessels or efferent ducts
Epidemiology
- Mean age 63 years (range 46 to 81 years) (Am J Surg Pathol 1999;23:903)
Sites
- Epididymis is most common site
- Can involve rete testis, tunica vaginalis, tunica albuginea, spermatic cord
Etiology & Pathophysiology
- Exact cause not known
- Obstruction of epididymis or vas deferens ducts hypothesized to be initiating event
Clinical features
- Most common presentation is painless scrotal mass of long standing duration
- May have periodic pain but usually not a prominent feature
Diagnosis
- Suspected clinico - radiologically and confirmed histologically
Laboratory
- No specific laboratory feature
- Negative tumor markers for germ cell and sex cord stromal tumors
Radiology description
- Ultrasound helps delineate the lesion, though it may be difficult to exclude involvement of adjacent testis
- May appear solid or multicystic
Prognostic factors
- Benign nonneoplastic lesion
- No recurrence or progression has been reported
Case reports
- 55 year old man with paratesticular mass (Arch Pathol Lab Med 2003;127:E111)
- 55 year old man with smooth muscle hyperplasia of epididymis (J Surg Case Rep 2011;2011:10)
- 66 year old man with simultaneous leiomyoma and contralateral smooth muscle hyperplasia of epididymis (Pathologica 2009;101:119)
- Complex multilocular cystic lesion of rete testis, accompanied by smooth muscle hyperplasia, mimicking intratesticular Leydig cell neoplasm (Virchows Arch 2005;447:768)
- Smooth muscle hyperplasia of epididymis (Pathology 2003;35:454)
Treatment
- May be excised for diagnosis and treatment
- No further treatment required
Gross description
- Mean 2.5 cm, range 6 mm to 7 cm
- Discrete or ill defined nodules, fusiform or cordlike masses, thickened or diffusely enlarged paratesticular structures
Gross images
Images hosted on other servers:
Well circumscribed multicystic mass
Microscopic (histologic) description
- Irregular fascicles of smooth muscle in periductal, perivascular, interstitial or mixed pattern
- No cohesive interlacing growth pattern of leiomyoma
- May be associated with secondary myxoid change, calcification, hemorrhage, fibrosis
- May be associated with ectasia of involved ducts, microscopic adenomatoid tumor, vasitis nodosa
- No cellular atypia, no mitosis, no necrosis
Microscopic (histologic) images
Images hosted on other servers:
Columnar epididymal type epithelium
Cystic duct
Mass blends with ducts in epididymal tail
Immunohistochemistry & special stains
- Positive for smooth muscle markers but immunohistochemistry not particularly useful in differential diagnosis
Differential diagnosis
- Leiomyoma: well circumscribed interlacing fascicles of smooth muscle, which displace rather than encase / invade the adjoining structures
- Leiomyosarcoma: malignant tumor characterized by high cellularity, mitosis, necrosis and cellular atypia and associated with invasive features
