Objectives To describe a case of cystic dysplasia of the testis (CDT), an uncommon cause of scrotal swelling in the pediatric patient. Clinical, radiographic and pathologic findings are discussed and the 10 previously re- ported cases are reviewed. Methods A 4-year-old boy presented with asymptomatic scrotal swelling and was found to have a palpable mass in the upper pole of the right testicle with evidence of partial transillumination. A scrotal ultrasound re- vealed testicular enlargement with multiple cystic changes suggesting teratoma and operative exploration was recommended. Results Intraoperative findings included a multicystic mass in the right testicle with minimal normal testicular parenchyma. Subsequent inguinal orchiectomy was performed and pathologic examination revealed a be- nign, multilobulated configuration of cysts in the region of the rete testis with atrophy of the surrounding tes- ticle. These findings were similar to those found in previously reported cases of CDT. Ipsilateral renal agenesis, a commonly associated anomaly, was also discovered in our patient. Conclusions CDT is a rare cause of the pediatric scrotal mass that requires a high index of suspicion for diag- nosis based on well-described clinical and sonographic findings. When feasible, a testicular-sparing approach should be considered and all patients should undergo evaluation for associated urologic anomalies.