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Pelvis » Scrotum And Testicles
Cystic dilatation of the Rete Testis
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Author(s) :
Douglas Brown, MD
Presentation A 51-year-old male presents with left scrotal enlargement.
Caption: Transverse sonogram of the left testicle
Description: Several small cystic spaces are seen clustered in the periphery of the left testicle.
Caption: Sagittal sonogram with color Doppler of the left testicle
Description: The elongated nature of the clustered cystic spaces is evident in this sagittal view. No flow is detected within the cystic spaces.
Caption: Sagittal sonogram of the left testicle and superior to the left testicle
Description: A portion of a large epididymal head cyst is seen superior to the left testicle. The cystic spaces within the testicle are not seen in this plane.
Differential Diagnosis Cystic dilatation of the rete testis
Intratesticular varicocele
Adenocarcinoma of the rete testis
Final Diagnosis Cystic dilatation of the rete testis and large epididymal cyst
Discussion Cystic dilatation of the rete testis is a benign entity that can usually be diagnosed based on its typical sonographic appearance. Other terms have been used for this abnormality, including ectasia, cystic ectasia, tubular ectasia, cystic transformation, or cystic dysplasia of the rete testis.  It usually consists of multiple tiny cystic spaces clustered in or adjacent to the mediastinum testis.  The cystic spaces are often only 1 to 3mm but occasionally can be larger.   The finding can be unilateral or bilateral.  It occurs over a wide age range but seems to be more common in older men.  The majority of cases have multiple or large ipsilateral epididymal cysts.
It has been suggested that these cysts are related to epididymal obstruction, though a primary developmental abnormality has also been suggested.
The typical sonographic appearance usually suffices for diagnosis and no intervention is needed.  There is little in the way of differential diagnosis. Varicoceles can rarely be intratesticular and might also appear with multiple cystic spaces.  The cystic spaces would likely connect and presence of flow by Doppler should allow the correct diagnosis.  Adenocarcinoma of the rete testis can have a multicystic appearance but it is quite rare and generally not a consideration.  The presence of nodular areas within the cyst may be a clue to this rare diagnosis.
Case References 1. Brown DL, Benson CB, Doherty FJ, et al. Cystic testicular mass caused by dilated rete testis: sonographic findings in 31 cases. AJR Am J Roentgenol 1992; 158:1257-1259.
2. Burrus JK, Lockhart ME, Kenney PJ, Kolettis PN. Cystic ectasia of the rete testis: clinical and radiographic features. J Urol 2002; 168:1436-1438.
3. Cho CS, Kosek J. Cystic dysplasia of the testis: sonographic and pathologic findings. Radiology 1985; 156:777-778.
4. Dogra VS, Gottlieb RH, Rubens DJ, Liao L. Benign intratesticular cystic lesions: US features. Radiographics 2001; 21 Spec No:S273-281.
5. Fisher JE, Jewett TC, Jr., Nelson SJ, Jockin H. Ectasia of the rete testis with ipsilateral renal agenesis. J Urol 1982; 128:1040-1043.
6. Nistal M, Regadera J, Paniagua R. Cystic dysplasia of the testis. Light and electron microscopic study of three cases. Arch Pathol Lab Med 1984; 108:579-583.
7. Smith SJ, Vogelzang RL, Smith WM, Moran MJ. Papillary adenocarcinoma of the rete testis: sonographic findings. AJR Am J Roentgenol 1987; 148:1147-1148.
8. Weingarten BJ, Kellman GM, Middleton WD, Gross ML. Tubular ectasia within the mediastinum testis. J Ultrasound Med 1992; 11:349-353.
9. Weiss AJ, Kellman GM, Middleton WD, Kirkemo A. Intratesticular varicocele: sonographic findings in two patients. AJR Am J Roentgenol 1992; 158:1061-1063.
Follow Up Not applicable