Cystic dysplasia of the rete testis: A rare mimicker of malignancy in pediatric patients

Abstract

Cystic dysplasia of the rete testis is a rare congenital condition, commonly affecting children, and often presents as a painless scrotal swelling or testicular mass resembling malignancy. Frequently linked with genitourinary anomalies like ipsilateral renal agenesis or dysplasia. We report 14-year-old boy with progressive left scrotal swelling since early childhood. Imaging studies revealed cystic loculations displacing the testicular parenchyma, with normal tumor markers. A left orchidectomy was performed due to extensive lesion and complete parenchymal displacement, with histopathology confirming CDT. This case highlights the role of advanced imaging in accurate diagnosis and the importance of a multidisciplinary approach in management.

1 Introduction

Cystic dysplasia of the rete testis (CDT) is an uncommon, benign testicular condition predominantly affecting children and often presenting as painless scrotal swelling or a testicular mass, often mimicking malignant lesions. It is typically associated with genitourinary anomalies, most frequently ipsilateral renal agenesis or dysplasia. High-frequency ultrasonography (7.5–10 MHz) plays a crucial role in diagnosis, revealing multiple small cysts of varying sizes within the rete testis, surrounded by normal or compressed testicular tissue. The exact cause of CDT is not fully understood, and treatment options range from active surveillance to testis-sparing surgery or, in rare cases, orchiectomy, depending on the lesion’s characteristics and associated complications.

2 Case report

A general practitioner for evaluation of a left scrotal swelling ( Fig. 1 ) using inguinal ultrasonography referred a 14-year-old patient. History-taking revealed progressive enlargement of the left hemiscrotum since the age of 3, but this had been neglected by the parents. There were no inflammatory signs, such as redness or warmth, and the patient reported no tenderness upon palpation.

Ultrasound findings revealed multiple intra-testicular cystic loculations on the left testis, containing anechoic fluid, with no uptake on color Doppler. These cysts lacked septations or vegetations and displaced the surrounding testicular parenchyma ( Fig. 2 ). A biological workup was performed to exclude a tumoral origin. The results were within normal ranges, with plasma β-HCG <0.100 mIU/mL and AFP at 0.80 IU/ml

For further characterization, a scrotal MRI was performed. The MRI included the following sequences: 3D T2 (sagittal, axial, and coronal), 3D T1 (sagittal, axial, and coronal), diffusion-weighted imaging, and gadolinium-enhanced sequences. The left testis was found to be enlarged, measuring 49.5 x 31 × 30 mm (H x AP x T), corresponding to a volume of 24 cc. It contained multiple contiguous micro- and macro-cystic lesions, described as hyperintense on T2-weighted images, hypointense on T1-weighted images, with no restriction on diffusion and no enhancement after gadolinium injection. These cysts displaced the normal testicular parenchyma peripherally, with the entire lesion measuring 47 x 28.5 × 27 mm. The right testis was normal in size, morphology, and signal, with no focal anomalies ( Fig. 3 ). To further investigations, the patient was recalled to assess a potential underlying renal anomaly. An abdominal ultrasound revealed left ureteral dilatation measuring 10 mm, with an empty left renal fossa ( Fig. 4 (A–B)). A CT scan of the abdomen and pelvis was performed to locate the left kidney, showing a small left kidney measuring 30 mm in its longest axis. with evidence of destruction and a calcified wall, along with persistent ureteral dilatation of 10 mm ( Fig. 4 (C-D-E) ). Due to the extensive cystic lesions and complete displacement of the normal testicular parenchyma, the pediatric surgeon opted for a left orchidectomy. The specimen from the left orchidectomy consists of a testicle with its attached spermatic cord. The testis appears grossly enlarged and, upon bisection, reveals multiple cystic spaces of varying sizes filled with clear, gelatinous fluid. The cystic spaces are separated by thin septa, without evidence of solid nodules, hemorrhage, or calcifications. The external surface of the testis is smooth, with no irregularities or discoloration. The spermatic cord appears grossly unremarkable. ( Fig. 5 (A) ). Histological analysis confirmed the diagnosis of cystic dysplasia of the rete testis by showing in the middle part of the testicle, cystic spaces lined with simple or flattened cuboidal epithelium without atypia were observed, separated by fibrous septa. The testicular parenchyma displaced to the periphery contains seminiferous tubules housing Sertoli cells and spermatogonia, along with interstitial tissue containing a few Leydig cells ( Fig. 5 (B) ).