Cystic dysplasia of the testis with terminal ureterectasis and renal absence: evidence of involution of a dysplastic kidney? (Case Report).

Abstract: Cystic dysplasia of the testis is a rare congenital anomaly, only 29 cases having been previously reported. We report a case of cystic dysplasia of the testis and absent ipsilateral kidney, but an ipsilateral ectatic terminal ureter, suggesting involution of a dysplastic kidney as a reason for the apparent renal agenesis.

Key Words: cystic, dysplasia, mesonephric duct, testes

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Cystic dysplasia of the testis or ectasia of the rete testis is a rare congenital anomaly. (1) We found only 29 histologically confirmed cases previously reported. (1-3) The lesion is analogous to the development of cysts in renal dysplasia in that both lesions are believed to be the result of an abnormality of connection of the mesonephric duct with the respective organ. (1) Indeed, a spectrum of associated ipsilateral renal anomalies are usually reported, the most common being absence of the kidney. The following case of cystic dysplasia of the testis and absent ipsilateral kidney, but an ipsilateral ectatic .terminal ureter, suggests involution of a dysplastic kidney as a reason for the apparent renal agenesis.

Case Report

A 5-year-old boy was referred because of the finding of an asymptomatic right testicular enlargement of indeterminate duration. High-resolution testicular ultra-sonography showed cysts that were uniform throughout the testis (Fig. 1). Serum levels of tumor markers (AFP and B-hCG) were within normal limits. A right orchiectomy was done via an inguinal incision. The testicle was enlarged, measuring 3 X 1 X 1 cm, and rubbery in consistency. On longitudinal sectioning, the testis was characterized by elongated, radially oriented, pink cystic spaces spreading from the mediastinum and compressing the normal testicular parenchyma to only a thin rim, the appearance being reminiscent of renal dysplasia. Histologic examination of the testis confirmed the presence of cystic spaces lined with flattened cuboidal epithelium. A subsequent renal and bladder ultrasound examination showed no evidence of a right kidney, but distinct ectasia of the ipsilateral terminal ureter (Fig. 2). Vesicoureteral reflux was not identified on cystography. A radionuclide renal scan showed no evidence of a right kidney. The child has remained well during a 2-year follow-up.

Discussion

The embryology, histology, and management of this fascinating anomaly has now been well described, as well as its association with an ipsilateral renal abnormality. (1-3) The lesion of cystic dysplasia of the testis appears to occur because of an abnormality of connection of efferent ductules, which are of mesonephric duct origin, and the rete testis, which is derived from the gonadal blastoma. (4,5) Cystic dysplasia is most precisely termed cystic dysplasia of the rete testis. (4) The mechanism of development is similar to that of renal dysplasia in which the abnormality develops at the juncture of the mesonephnc duct derivative, the ureteral bud, with the metanephrogenic mesenchyme. (4) With the exception of two cases described by Nistal et al, (4) all of the reported cases of histologically documented cystic dysplasia of the testis in which the upper urinary tract is described have reported ipsilateral absence or dysplasia of the kidney.

Patients with cystic dysplasia of the testis and an absent kidney are frequently reported as having agenesis of the kidney. (2,3) However, in only one patient with an absent kidney was cystoscopy done, which showed absence of the ipsilateral trigone. (6) Two patients with cystic testicular dysplasia and an ipsilateral dysplastic kidney have been reported on follow-up to no longer have an identifiable kidney. (2,3) This is not surprising since in patients at 5 years of age, 54% of known dysplastic kidneys can be expected to no longer be imaged by ultrasonography because of involution of the organ. The finding in our patient of a dilated terminal ureter and an absent kidney would indicate involution of a dysplastic kidney.

The best approach for management of cystic dysplasia of the testis is not known. Treatment includes orchiectomy, resection of the lesion, and nonoperative management with serial follow-up imaging. (2,7,8) A rational management plan has been outlined by Kogan, (9) who stressed that if a conservative approach is to be followed, precise high-resolution ultrasonography is a requisite. If strict testicular ultrasonic criteria are met, along with normal levels of tumor markers and additional sonographic evidence of mesonephric abnormalities, such as an ipsilateral cystic kidney, a nonoperative approach or testis-sparing excision of the lesion can be considered. When the lesion replaces most of the testis, orchiectomy may still be the best choice.

Accepted December 5, 2001.

References

(1.) Garrett JE, Cartwright PC, Snow BW, Coffin CM. Cystic testicular lesions in the pediatric population. J Urol 2000;163:928-936.

(2.) Wojcik L.J, Hansen K, Diamond DA, et al. Cystic dysplasia of the rete testis: A benign congenital lesion associated with ipsilateral urological anomalies. J Urol 1997;158:600-604.

(3.) Robson WL, Thomason MA, Minette L.J. Cystic dysplasia of the testis associated with multicystic dysplasia of the kidney. Urology 1998;51: 477-479.

(4.) Nistal M, Regadera J, Paniagua R. Cystic dysplasia of the testis. Light and electron microscopic study of three cases. Arch Pathol Lab Med 1984; 108:579-5 83.

(5.) Glantz L, Hansen K, Caldamone A, Medeiros L.J. Cystic dysplasia of the testis. Hum Pathol 1993;24: 1142-1145.

(6.) Leissring JC, Oppenheimer R.O. Cystic dysplasia of the testis: A unique congenital anomaly studied by microdissection. J Urol 1973;110:362-363.

(7.) Toffolutti T, Gamba PG. Cecehetto G, Talenti E, Tehaprassian Z. Testicular cystic dysplasia: Evaluation of 3 new cases treated without surgery. J Urol 1999;162:2146-2148.

(8.) Noh PH, Cooper CS, Synder HM III. Conservative management of cystic dysplasia of the testis..! Urol 1999;162:2145.

(9.) Kogan SJ. Testicular cystic dysplasia: A diagnostic and therapeutic enigma?.! Urol 1999;162:2 149 (editorial).

RELATED ARTICLE: Key Points

* Cystic dysplasia of the testis is rare, with less than 30 cases reported.

* The lesion is specifically a cystic dysplasia of the rete testis.

* The lesions are the result of an abnormality at the juncture of the mesonephric duct and the gonadal blastoma.

* Dysplastic kidneys, which form by an abnormal mesonephros/metanephros interface abnormality, are similar anomalies.

* Involution of a dysplastic kidney resulting in renal absence is suggested by our case.

From the Department of Urology, University of Arkansas for Medical Sciences, and Arkansas Children's Hospital, Little Rock, AR.

Reprint requests to John F. Redman, MD, Department of Urology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Slot 540, Little Rock, AR 72205-7199. Email: [e-mail]

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