Transverse testicular ectopia (TTE) associated with persistent Mullerian duct syndrome (PMDS) is a rare anomaly that can be encountered during laparoscopy for nonpalpable testis or during exploration for groin hernias. About 100 cases of TTE have been reported in published studies. The initial finding at laparoscopy may give the impression of a unilateral absent testis if one is not aware of the possible testicular crossing to the contralateral side. Such cases are likely to be missed without the usage of diagnostic laparoscopy in all cases of impalpable testes.
A 7-month-old boy presented with right inguinal hernia and left impalpable testis. Laparoscopy revealed an absent left testis with a closed internal ring. However, on inspecting the right side, we encountered a testis lying above the opened internal ring (Fig. 1). Pulling on that testis revealed another testis that was attached to the crossed testis by a remnant of a Mullerian tube (Figs 2 and 3). The uterus and cervix were split in the midline laparoscopically, and both testes with a rim of Mullerian tissue were sited in their ipsilateral hemiscrotum. He had a brother with persistent Mullerian syndrome, who presented with right impalpable testis and left inguinal hernia at the age of 2 years.
A 6-month-old boy presented with right inguinal hernia and left impalpable testis. Laparoscopy revealed an absent testis on the left side and two testes on the right attached to Mullerian remnants. Through right groin incision, the uterus and cervix were split in the midline, and the left testis was brought to the ipsilateral scrotal sac laparoscopically through a direct route. He had a brother with persistent Mullerian syndrome who presented at the age of 9 months with right impalpable testis and left inguinal hernia.
An 8-month-old baby presented with right-sided inguinal hernia and nonpalpable left testis with penoscrotal hypospadias. His karyotype was 46,XY. The laparoscopic findings were that of crossed testicular ectopia and persistent Mullerian remnants. Fallopian tubes were present, but the uterus was less muscular than that of previous cases. The uterus split the midline laparoscopically, bringing both testes to the ipsilateral side through a direct approach medial to the internal ring.
TTE is a rare form of testicular ectopia. It was first reported by Von Lenhossek in 1886 1. The finding of PMDS with TTE is a clinically rare anomaly that can be encountered during laparoscopy for nonpalpable testis or during exploration for groin hernias. The anomaly combines defects in regression of fetal Mullerian structures with aberrant testicular descent. The hypotheses for PMDS causation include failure of synthesis or release of Mullerian inhibiting substance (MIS), failure of end organs to respond to MIS, or a defect in the timing of the release of MIS 2. TTE was found to occur in animal models when the testicular aspect of the gubernaculum was detached from the testis. In these animal models, the detached testis crosses the midline to descend into the contralateral scrotum. Hence, it could be postulated that defective ipsilateral gubernacular development might predispose to TTE 2. Several other hypotheses have been reported that could explain the genesis of TTE, which include the emergence of both vasa deferentia from one side 3, the development of both testicles from the same germinal ridge 4, and defective implantation of the gubernaculum testis or obstruction to the inguinal ring 5.
The relationship between PMDS and TTE is less clear. The transabdominal phase of testicular descent is thought to be controlled by MIS, which is secreted locally by each testis (paracrine effect). Fusion of the Mullerian ducts to form a uterus occurs embryologically at the same time as development of the vas deferens 6. We postulate that an earlier development of one ipsilateral Mullerian structure may pull the contralateral testis toward the developed Mullerian side. The familial incidence of TTE in brothers and twins suggests the likelihood of autosomal recessive inheritance 7. The initial findings at laparoscopy of no testicular tissues with no evidence of testicular vessels or vas deferens give the impression of an absent testis. It is therefore essential to explore the pelvis and the course of testicular descent before labeling the case as an absent testis. The most commonly described technique for TTE is the modified Omberdan technique in which the ectopic testis is placed in the correct hemiscrotum through a window in the scrotal septum. However, laparoscopy has been reported to aid in placing the ectopic testis with the attached rim of Mullerian structures through a direct route medial to the internal ring in the ipsilateral hemiscrotum 8,9. One should be careful during the splitting of the uterine remnants to avoid injuring the vas deferens and its blood supply at the base of the Mullerian remnants as both vasa deferentia lie very close to each other. In two of our cases the Mullerian structures were fully developed, and in one case the Mullerian structures were hyposplastic. We suggest splitting the uterine tissue leaving about 1 cm above the base of the uterus and use the direct route to place the testis into the ipsilateral hemiscrotum. As malignancy has never been reported in the retained Mullerian ducts, there is no need for its removal as this may endanger the blood supply to the testes 10. Six cases of testicular tumor in TTE have been reported in adults in which the status of the Mullerian remnant has not been specified. Histology revealed seminoma in five and mixed tumor in one 11. The relatively high incidence of testicular tumors in such a rare entity of testicular descent necessitates the need for close follow-up of such cases.
TTE with PMDS might be encountered during laparoscopy for impalpable testes or during groin exploration for inguinal hernia. Awareness of this anomaly and understanding of the embryological process of testicular descent and its associated aberration are prerequisites for the proper management of this rare phenomenon.
Conflicts of interest
There are no conflicts of interest.
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