Undescended Testis

Introduction

Undescended testis is one of the most common congenital anomalies in boys affecting about 4% full-term newborn males. It is more common in preterm babies. One type of undescended testis is ascending testis, in which patients are born with a normal testicular position but the testis later ascends out of the scrotum. This is more common in patients with obesity.

Causes and Risk Factors

No specific cause is identified so far, but there are some known risks factors for congenital undescended testis, such as prematurity, low birth weight, being the first-born child and maternal hypertension. Congenital undescended testis constitutes about 74% while ascending testis constitutes about 13% of all undescended testis cases in Hong Kong.

Signs and Symptoms

Undescended testis is usually detected by physical examination in the newborn period. Ascending testis is usually detected at an older age during assessment in the Student Health Service (SHS). Sometimes parents may notice scrotal asymmetry, in which one side of the scrotum looks smaller or flatter than the other side.

Diagnosis

Diagnosis is made by physical examination by a paediatric surgeon to check the position and status of the testis and to look for other associated anomalies. Most of the time, a proper physical examination alone is sufficient to make the diagnosis, and no additional investigation is required. On rare occasions, pre-operative imaging, such as ultrasound or magnetic resonance imaging (MRI), may be arranged in selected cases.

Treatment and Management

During your visit, a paediatric surgeon will perform a physical examination on your child's external genitalia to establish the diagnosis and decide on the treatment plan.

If undescended testis persists beyond 6 months of age, surgical treatment to bring the testis down to the scrotum is indicated. The surgery, known as orchidopexy, will be performed under general anaesthesia. There are different methods of orchidopexy and the exact method will be determined by the surgeon after assessing your child. The surgical procedure and its risks will be explained, and surgical consent will be obtained from you. Appointments for anaesthetic assessment and surgery will be arranged.

Is it necessary to add the procedures of the surgery? - not necessary to state the exact procedure as it will be different according to the patient's condition and physical findings; this is added to the text as above

Follow-up Care

Follow-up appointment at HKCH or other hospitals will be arranged after the surgery. If surgery is not indicated, a follow-up appointment at HKCH or other hospitals may be arranged to monitor the testicular position.

Reference

Tang, M. Y., Wong, Y., Pang, K. K., & Tam, Y. (2021). Orchidopexy for congenital and acquired undescended testes - Long-term follow up needed. Surgical Practice, 25(3), 165-169. https://doi.org/10.1111/1744-1633.12511

Acknowledgement

Principal author: Dr Tang Yeuk-lam Michelle on behalf of Department of Paediatric Surgery, HKCH

Initial posting: Oct 2026

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