[TRANSVERSE TESTICULAR ECTOPIA WITH INCIDENTAL TESTICULAR TUMOR, DISCOVERED UPON SYMPTOMATIC TESTICULAR TORSION].

Transverse testicular ectopia is a condition in which a testicle crosses the midline and descends through the contralateral inguinal canal, with both testes in the same scrotal compartment. It is reported to be present in about 2% of persons who present with non-palpable testicles. Most transverse testicular ectopia patients undergo orchiopexy in early childhood; however, in rare cases, they are diagnosed in adulthood upon detection of testicular tumors.A 40-year-old man visited our hospital complaining of right abdominal pain. His right testis was palpable in the right scrotum; however, the left scrotal compartment seemed empty and there was a painful mass on the upper part of the right scrotal compartment. Computed tomography showed that both spermatic cords traversed through the right inguinal canal, and transverse testicular ectopia was diagnosed. Ultrasonography showed absent left testicular circulation on the upper part of the right scrotum. Upon diagnosis of left testicular torsion, emergency surgery was conducted. In the right scrotum, there was a normal right testicle, and a necrotic left testicle which was twisted 180 degrees on its axis, towards the cranial side. Histopathology of the excised left testicle revealed an incidental seminoma, pT1. Tumor markers following surgery were negative, and there was no evidence of recurrence observed with two years and five months of follow-up.Non-palpable testicular torsion may also be a transverse testicular ectopia. Therefore, it is necessary to consider malignant tumors based on the patient's age.