Is routine excision of testicular remnants in testicular regression syndrome indicated?

Undescended testicles are a common finding in full-term male infants. In the majority of these infants, the testicle spontaneously descends in the first year of life. However, in others, it remains impalpable in an abnormal position or there may only be a small abnormal testicular remnant present. For these infants there is still controversy surrounding inguinal exploration and/or excision of these testicular remnants at the time of operative intervention. The controversy centres on their potential future malignant potential.

The aim of the study was to ascertain the incidence of the presence of either germ cells (GCs) or seminiferous tubules (SNTS) in the excised testicular remnants. This was performed at a paediatric surgical tertiary centre and contributes to the evidence base for this condition.

A retrospective data analysis occurring over a 15-year period of all excised testicular remnants. The testicular remnants were analysed for age, laterality, histological analysis and clinical diagnosis. Subset analysis included subdivision into both intra-abdominal or inguinal positions, and age ranges. Statistical analysis was using Fisher's exact test and a P-value of <0.05 was considered to be significant.

A total of 140 paediatric male patients were identified as having had a testicular remnant excised during the study period. Their demographics and also the main results are summarised in the overall summary Table. The mean age at intervention was 3.5 years (range: 3 months to 17 years). A total of 132/140 of the boys underwent excision of an inguinal testicular regression syndrome (TRS) remnant and 8/140 an intra-abdominal remnant. Comparison of these two groups revealed no significant difference for the presence of GCs (12 (9%) vs 2 (25%), P = 0.18). However, intra-abdominal TRS remnants were much more likely to contain SNTs (27 (21%) vs 7 (88%), P = 0.0002). There was no decreased incidence of either GCs or SNTs with increased patient age.

The main reason for the debate over the management of boys with TRS is the variable incidence of viable germ cells reported in different studies: it has been reported between 0 and 16%. The incidence of GCs (10%) and also SNT (24%) in the present series therefore contributes to this evidence base and is in the middle of this range. It is still unclear as to whether these remnants have a future malignancy risk, as there is only one case of intratubular germ cell neoplasia (ITGCN) in a testicular remnant reported in the literature and this was not immunohistochemically supported. The presence of ITGCN, although considered as a precursor to the development of a testicular germ cell tumour in adult patients, has also not been established in paediatric patients. The natural history of the GCs in TRS specimens is also unknown. In the present series, however, there was no decreased incidence demonstrated with increased patient age, although older patient numbers limited this subset analysis. Despite this controversy, as these patients were already under general anaesthetic, an inguinal exploration and excision of any TRS remnant that was present did not significantly increase the operative procedure or time, and removed any potential malignancy risk.

This evidence supports the exploration and excision of inguinal testicular remnants, as one in ten boys have GCs present and one in four have SNTs, which may have a potential future malignant transformation risk.