Sonographic Findings of Smooth Muscle Hyperplasia of the Epididymis

Abstract

mooth muscle hyperplasia of the epididymis is a rare condition and is seen as non-neoplastic proliferation of smooth muscle, which forms smooth muscle fascicles arranged in a periductal, perivascular, interstitial, or mixed pattern. 1Although several cases of smooth muscle hyperplasia of the epididymis have been described in the pathologic literature, 1-3 to the best of our knowledge, sonographic findings have not been described. We report the sonographic findings of a case of smooth muscle hyperplasia of the epididymis that presented as a solid mass. Case ReportA 47-year-old man was admitted with a 4-week history of a left scrotal mass. There was no history of genitourinary problems. A physical examination revealed the presence of a hard nontender mass in the tail of the left epididymis. The mass measured approximately 1 cm in diameter. The right testis and epididymis were normal. Scrotal sonography was performed with a 5-to 12-MHz linear array transducer attached to an iU22 scanner (Philips Healthcare, Bothell, WA). Gray scale sonography showed the presence of a well-defined solid mass in the left epididymal tail. The mass showed a heterogeneous echo texture with echogenicity similar to that of the adjacent testis and had a thin hypoechoic rim ( Figure 1A). On color Doppler sonography, no blood flow within the mass was depicted. An increase in perilesional blood flow was seen ( Figure 1B).The patient underwent surgical excision of the mass and a left epididymectomy. A gross pathologic examination showed a firm yellowish-whitish mass measuring 1 × 0.8 × 0.6 cm in the epididymal tail ( Figure 1C). A microscopic examination showed a proliferation of smooth muscle encasing dilated epididymal ducts (Figure 1, D and E). The pathologic diagnosis was smooth muscle hyperplasia of the epididymis.

Adnexal smooth muscle hyperplasia resulting in non-traumatic testicular dislocation: A case report

“…Some reports describe the mass with a thin hypoechoic rim on ultrasound. 5 In our case, sonographic findings demonstrated a discrete mass with similar echogenicity to the adjacent testis and adequate surrounding flow on Doppler. Ultimately, histopathological evaluation is the definitive method to establish diagnosis and to distinguish this mass from other (potentially malignant) adnexal neoplasms.…”

“…This case describes a unique presentation of testicular adnexal SMH. This is a non-neoplastic growth of smooth muscle that was first described clinically as a mimic of testicular adnexal neoplasm in 1999 through a sixteen-case cohort by Barton et al 2 Since then, a handful of case reports have further described salient histopathological 4 and radiologic 5 features. In 2020, Alruwaii et al published the second-largest case series with twelve patients.…”

“…However, differentiating between SMH and leiomyoma, adenomatoid neoplasm, or papillary cystadenoma may be difficult on imaging alone. 2 , 5 Sonographic findings of SMH typically include a discrete mass from the testis with heterogeneous echotexture and echogenicity similar to the testis. Some reports describe the mass with a thin hypoechoic rim on ultrasound.…”