Correct answer
D Observation
Based on the history and findings, this boy likely has testicular regression syndrome (TRS), also referred to as a “vanishing testis” from an antenatal ischemic injury to the descended right testicle either from torsion or vascular thrombosis. While the increased risk of malignancy associated with undescended testicles is well established, it is unclear whether a similar risk exists for descended testicles that have undergone regression in response to an ischemic injury.
A recent systematic review of TRS included nearly 1500 patients with histologic data on their resected testicular remnants. The patient attributes characterized were age at resection, sidedness and anatomic location (intraabdominal, inguinal or scrotal) of the remnants. The study found that only 5.3% and 10.7% of patient specimens had viable germ cells and seminiferous tubules respectively, with no relationship between age at resection and viability. Other histologic findings included dystrophic changes of hemosiderin-laden macrophages, fibrosis and calcification. There was no evidence of cellular atypia in any specimens. 67% of specimens were left sided. The anatomic location of remnants was as follows: 66% inguinal, 27% scrotal and 7% intraabdominal.
The natural history of a TRS remnant with viable elements is unknown. Some authors argue that any germ cell or tubular viability confers a future risk of malignant transformation and thus all remnants should be excised. However, there is not a single case report of neoplasia in an excised remnant, nor of a later diagnosis of cancer in an adult with a retained remnant. If the risk of neoplastic transformation is primarily related to maldescent and not to the vascular event causing testicular regression, then the scrotal remnant has no additional malignant risk and can be safely observed. The same may not be true for inguinal and intra-abdominal remnants, for which excision should be considered, especially if the remnant would be otherwise inaccessible for self-examination. There is no role for hormone treatment in this scenario.
