Tubular ectasia of the testicle: sonographic and MR imaging appearance

Ectasia of the seminiferous tubules at the level of the mediastinum is a recently recognized benign condition of the testicles. Although it may have typical sonographic features, the condition can at times be difficult to distinguish from tumors on the basis of sonography. We describe the sonographic and MR appearance of this condition in seven men in whom we were able to distinguish tubular ectasia from tumors of the testicles on the basis of the imaging findings.

Ectasia of the seminiferous tubules was histologically proved in a man who had an intratesticular mass seen on sonograms and MR images. We analyzed the sonographic and MR imaging features in this man and in six others who had similar imaging findings but did not have biopsy proof of tubular ectasia.

The first patient was a man with bilateral findings who had a unilateral orchiectomy that revealed ectasia of the seminiferous tubules. Spermatocelectomy was performed in another man whose testis was normal on surgical inspection and on subsequent follow-up. Imaging findings have remained unchanged in one man with 3-year imaging follow-up and in three men with clinical follow-up of 8-22 months. One patient was lost to follow-up. At presentation, most of the men were more than 55 years old. All had a scrotal mass typical of a spermatocele on physical examination, with normal testes when the testes could be palpated. The spermatocele was larger than 4 cm in six of 11 involved epididymides. On imaging, in five of the seven patients, the intratesticular process was bilateral, involved the mediastinum testis, began at the periphery adjacent to the spermatocele, and extended for a variable distance within the testis. On sonograms, the lesion was hypoechoic with coarse internal echoes. MR imaging of six of the seven patients showed characteristic findings and allowed the identification of two additional testicles with tubular ectasia that were missed sonographically. Lesions had a homogeneous signal similar to that of the coexisting spermatocele with all pulse sequences. They were hypointense relative to the testis on T1- and proton density-weighted images and, unlike tumors, were not visible on T2-weighted images.

Our experience suggests that ectasia of the seminiferous tubules can be distinguished from testicular tumor on the basis of characteristic clinical, sonographic, and MR imaging findings. Thus, orchiectomy is unnecessary to establish the diagnosis and to rule out tumor.