The line of testicular descent extends from the level of the lower pole of the kidney to the level of the scrotal neck. Any location of the testis outside this pathway should be classified as testicular ectopia [4, 12, 13]. However, clinically palpable extrascrotal testes should be examined meticulously to differentiate undescended, retractile, ectopic, and ascending testes from each other, with assistance of the other tools of diagnosis, because management could be different [1, 2]. The reported positions of ectopic testis include superficial inguinal pouch, perineum, femoral region, contralateral hemiscrotum, pubopenile (pubopenile, suprapubic, prepenile, or penile) region, and anterior abdominal wall [2, 3, 14]. However, a new classification should be implemented to withstand all the reported sites of testicular ectopia including the anterior abdominal wall ectopic testes for differentiation from the other entities of abnormal testicular descent [6, 7, 15].
Age of presentation of testicular ectopia is variable between the neonatal period and adulthood [13, 14, 16]. Abdominal positions of testicular ectopia are extremely rare, where a few cases have been reported so far . Abdominal ectopic testis may be located, either on the inner surface of the anterior abdominal wall to be known as a preperitoneal testicular ectopia [17,18,19], at the subcutaneous spaces mimicking Spigelian hernia [4, 20], or as interstitial abdominal wall testis which has been recently reported . The preperitoneal positions have been increasingly detectable with the use of laparoscopy which represents the most accurate tool for management of the impalpable and intraabdominal testes . Surgical significances of abdominal ectopic testis may differ from the abdominal undescended testis due to its relatively high and aberrant positions that may render laparoscopic management technically difficult. Preperitoneal locations are exceptions of the well-known definition of ectopic testis, where the testis may not traverse the inguinal canal [15, 18, 19]. Instead, it loops inside the abdominal cavity and resides in unusual sites. Our perspective is to differentiate it from the abdominal undescended testis by its location away from the line of normal testicular descent. Two current cases with preperitoneal position were treated laparoscopically with difficult manipulations that resulted in testicular atrophy in one case. So, the first priority in laparoscopy should go for preservation of the testicular vessels. In cases of inadvertent damage of the testicular blood supply due to unfamiliar position or adhesions to the surroundings, Fowler-Stephen operation could be a valid alternative.
Based on its clinical and surgical criteria, inguinal ectopic testis could be differentiated from cryptorchidic/undescended, retractile, and ascending testes. Surgically, it is the commonest form of testicular ectopia. The proposed mechanism is that the testis strays the line of descent to the superficial inguinal pouch after exiting the external inguinal ring . Although it could be suspected from the clinical findings, the diagnosis of ectopic inguinal testis could be confirmed only by the findings of surgical exploration similar to the current cases. Controversies have been raised by Murphy and Butler to consider this type just as similar as the inguinal undescended testis depending mainly on its apparent anatomical location in the line of normal descent and a relatively shorter spermatic cord than the other ectopic variants [14, 18]. However, this postulation seems to be inaccurate, if we returned to the definitions and mechanisms of each pathology. So, we prefer to consider the superficial inguinal testis as an ectopic one, when it relocates upwards and laterally from the normal pathway. However, confirmation of the inguinal ectopic testis could be difficult due to failure of localization of the gubernacular inguinal attachments. So, we had to differentiate 5 cases from the current series into a separate group of indeterminate diagnosis of inguinal ectopic testis. However, owing to fulfilling the other criteria including the location away from the line of normal descent clinically and surgically, they were still having higher possibilities of being ectopic inguinal testes rather than any other anomalies of testicular descent.
Length of the spermatic cord of the ectopic testis seems to vary by position. It should be considered as a result rather than a cause of the anomaly, and it is relative to the predefined position by other factors such as the gubernacular attachment. Hence, it is very long for testes that are traversing distantly in certain sites such as the cases of perineal, abdominal wall, and transverse testicular ectopia [14, 20, 23]. However, it is relatively short in the case of the superficial inguinal testis which is located in the nearest site to the external inguinal ring.
The ascending testis is defined as a testis that permanently ascended upwards to the inguinal region after a documented history of previous scrotal location [9, 24]. It has been suggested that significant proportions of the testes that are treated by orchiopexy are due to ascending testes. The criteria in this definition exclude the possibilities of testicular ascent in our cases. Also, two peaks of orchiopexy have been reported at the ages of 2 and 10–11 years [7, 24], where the second peak has been attributed to the ascending testes. Accordingly, the relative low mean age (5.15 years) of the current series of inguinal ectopic testes could be another difference that they were not ascending testes. On the other hand, missed low lying undescended testes, gliding (pathological retractile testis), and retractile testes have been proposed to contribute to the major proportions of ascending testis rather than the ectopic testes [7, 15, 24].
Besides the increasingly reported abdominal ectopic testes and the controversial inguinal ectopic ones, other classic types of testicular ectopia are variably reported. Perineal ectopic testis is the commonest form of the non-inguinal testicular ectopia. An observation has been made from the reported cases in the literature and the current series that the perineal testis presents in a relatively older age than the other variants [13, 14, 25]. This finding could be attributed to the anatomical nature of the perineum where it could be missed on physical examination at early presentation. Femoral testis is very rare, located in Scarpa’s triangle with its cord is deep to the inguinal ligament, and may mandate a high index of clinical suspicion and demanding surgical dissection. Also, prepubic (prepenile or pubopenile and penile) testes are extremely rare variants [1, 23]. Transverse testicular ectopia is the most complex form due to several issues that should be considered in management including congenital fusions, difficult differentiation of the testes from each other, and association with other congenital anomalies such as congenital hernia and chromosomal abnormalities such as persistent Mullerian structures. However, introduction of laparoscopy and transseptal orchiopexy techniques has much alleviated these difficulties [1, 23, 26,27,28].
In contrast to the undescended testis, testicular ectopia has no chances for spontaneous resolution or conservative correction. In a few circumstances, however, complexity of the anomaly such as fusion of the structures with delayed presentation by infertility may prevent surgical correction [16, 26]. Otherwise, surgical correction is recommended as early as possible. Orchiopexy is usually simple due to the long spermatic cord which allows easy repositioning of the testis in the scrotum in most of the variants [1, 2, 14]. However, preperitoneal and transverse testicular ectopia may warrant laparoscopic assistance with technical difficulties [1, 26].
Our data showed variable age presentation between childhood and adulthood with more delayed presentations among the non-inguinal ectopic testes relative to the inguinal ectopic testes. Delayed presentation and diagnosis of testicular ectopia may come from different causes including inaccurate physical examination, non-specialized physicians, and lack of awareness of the primary healthcare physicians and families regarding these anomalies. Testicular ectopia has higher potential risks of infertility, malignancy, trauma, and torsion [1, 2, 13, 27]. In the current cases, two patients with a unilateral ectopic testis had infertility. Similarly, infertility has been reported with cases of unilateral ectopic testes [13, 14]. Although the post-pubertal ectopic testis may have a fairly normal size, it is prone to have markedly deficient spermatogenesis. This risk could be attributed to loss of the scrotal temperature-regulating effect, delayed presentation, and late orchiopexy. Also, the intrinsic histologic changes could be present owing to the congenital nature [13, 14].