Retractile Testis—Is it Really a Normal Variant? Piyush K. Agarwal, Mireya Diaz and Jack S. Elder*,† From the Division of Pediatric Urology, Rainbow Babies and Children’s Hospital, and Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine (MD), Cleveland, Ohio
Purpose: Retractile testes are thought to represent a normal variant of descended testes in prepubertal boys. We studied retractile testes to determine their natural history. Materials and Methods: We retrospectively reviewed the charts of 122 boys (mean age 5.4 years) who were referred for a suspected undescended testis and were found to have a retractile testis. A retractile testis was defined as a suprascrotal testis that could be manipulated easily into the scrotum and remained there without traction until the cremasteric reflex was induced. The boys were followed by annual examinations, which demonstrated the presence of retractile, descended (nonretractile) or undescended testes, and the presence or absence of a taut or inelastic spermatic cord in association with a retractile testis. Results: Of 204 retractile testes 61 (30%) descended (became nonretractile), 66 (32%) became UDTs and 77 (38%) remained retractile. Of the 62 retractile testes with a taut or inelastic spermatic cord 35 (56%) became UDTs. Of the 61 orchiopexies performed 8 (13%) showed a patent processus vaginalis. Boys in whom UDTs vs descended testes developed were a mean of 4.9 vs 6.6 years old (p ⫽ 0.001). The chance of spontaneous descent was 58% in boys 7 years or older, compared to 21% in boys younger than 7 (p ⬍0.0001). Conclusions: A retractile testis is not a normal variant. Retractile testes have a 32% risk of becoming an ascending or acquired undescended testis. The risk is higher in boys younger than 7 years old, or when the spermatic cord seems tight or inelastic. Boys with retractile testes should be monitored annually until the testes have clearly descended. Key Words: cryptorchidism, testis, urogenital abnormalities, child
he reported incidence of UDTs is 0.8% in 1-year-old boys.1 However, reported rates of orchiopexy exceed this incidence. It is estimated that 2% to 3% of males have undergone orchiopexy by age 14 to 17 years.2–7 Fenton et al reported a bimodal distribution for age at orchiopexy, with 2 peaks occurring at ages 2 and 11 years.7 Hack et al observed a similar bimodal distribution for age, with peaks at 2 and 10 years, and an overall mean age at referral of 6.6 years.8 The prevalence of older boys undergoing orchiopexy can be explained by the phenomenon of acquired UDT or ascending testis in boys with a previously documented intrascrotal testis. Theories to account for this phenomenon include a hyperactive cremasteric reflex, incomplete absorption of a patent processus vaginalis in boys with a retractile testis, fibrous adhesions to the spermatic cord following inguinal surgery and misdiagnosis of a congenital UDT as a retractile testis, and, hence, late recognition of congenital UDT.9 However, prior inguinal surgery and hyperactive cremasteric reflexes do not occur often enough to account for the frequency of ascending testis. Consequently, misdiagnosis has been a prevailing explanation.
T
Submitted for publication April 21, 2005. Study received institutional review board approval. * Correspondence: Division of Pediatric Urology, Rainbow Babies and Children’s Hospital, 11100 Euclid Ave., Cleveland, Ohio 44106 (telephone: 216-844-8455; FAX: 216-844-8179; e-mail: jack.elder@ case.edu). † Financial interest and/or other relationship with QMed, Watson and Silimed.
0022-5347/06/1754-1496/0 THE JOURNAL OF UROLOGY® Copyright © 2006 by AMERICAN UROLOGICAL ASSOCIATION
Retractile testes are traditionally considered to be a variant of normal testes that move spontaneously out of the scrotum but return to the scrotum spontaneously or with manipulation and remain there for a finite period.10 These testes usually become fully descended (nonretractile) at puberty and are thought to retain normal fertility. Retractile testes may be difficult to distinguish from incompletely descended testes (low-lying UDTs) or ectopic testes. The 3 physical signs favoring the presence of an incompletely descended testis over a retractile testis are smaller testicular size (compared to the contralateral testis), rapid retraction out of the scrotum upon release of the testis and testicular pain with manipulation of the testis into the scrotum. Wyllie claimed that the presence of 2 of these 3 criteria favored a diagnosis of incompletely descended testis.11 Therefore, a low-lying UDT or ectopic testis refers to a testis that may indeed be a UDT that is situated high within the scrotum (or low within the inguinal canal) at birth and only manifests as a UDT after somatic growth increases the distance between the testis and the scrotal sac. The theoretical mechanism of testicular ascent is that the spermatic cord has limited growth potential, perhaps because of fibrous persistence rather than disappearance of the processus vaginalis. The spermatic cord of the ascending testis fails to keep up with the somatic growth, and the testis moves out of the scrotum. These boys initially have a descended or possibly a retractile testis and are diagnosed with UDT later in childhood. We hypothesized that retractile testes may be abnormal in some cases and may represent a precursor to the development of an ascending testis. The aim
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Vol. 175, 1496-1499, April 2006 Printed in U.S.A. DOI:10.1016/S0022-5347(05)00674-9
RETRACTILE TESTIS
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FIG. 1. Outcomes of 204 retractile testes
of this study was to determine the ultimate fate of retractile testes. MATERIALS AND METHODS We retrospectively reviewed the charts of boys who were referred for evaluation of a suspected UDT, and who were found to have a retractile testis. A retractile testis was defined as a suprascrotal testis that could be manipulated easily into the scrotum and remained there without traction until the cremasteric reflex was induced. This study did not include boys who had a scrotal testis that retracted during physical examination secondary to a strong cremasteric reflex. An undescended testis was defined as a testis that could not be manipulated into the scrotum, or if pushed into the scrotum, retracted immediately out of the scrotum. The boys were followed by annual examination, which revealed retractile, descended (nonretractile) or UDTs and the presence or absence of a taut or inelastic spermatic cord in association with a retractile testis. In boys with UDTs orchiopexy was recommended. If a boy had a UDT on 1 side and a retractile testis on the opposite side, usually the retractile testis was subjected to scrotal orchiopexy to prevent a future ascending testis. This approach was used to avoid the need for long-term followup for the remaining retractile testis, and in patients with bilateral retractile testes to take advantage of a single general anesthetic and operative visit to secure both testicles within the scrotum. The presence or absence of a patent processus vaginalis was noted at the time of orchiopexy and documented. Patients completed followup if the testes had spontaneously descended or they were diagnosed with UDTs and underwent orchiopexy. All patients had a minimum followup of 1 year. Boys who had made only 1 office visit, had received human chorionic gonadotropin, were less than 1.6 years old at referral, had cerebral palsy or had previously undergone inguinal surgery were excluded. Statistical analyses comparing several groups were performed using the chi-square and Student t tests. We constructed Markov chain models to assess the time course of the retractile condition properly dealing with the bivariate (both testes) and competing risk nature of the data. We defined 3 states to assess events for each testis (left, right)
separately. The states corresponded to the situation of the testis as retractile, descended or undescended. Transition probabilities between states (ie probability of a change in patient status) during followup were calculated using the additive framework proposed by Aalen et al12 and its companion code in S-Plus®. Statistical significance in probabilities and time of occurrence of events were assessed via 95% confidence intervals. RESULTS A total of 204 retractile testes (unilateral 40, bilateral 82) in 122 boys were identified. Mean age at referral was 5.4 years (range 1.6 to 13.5). An additional 65 boys were excluded from the study, most commonly because of only 1 office visit. Of the 204 retractile testes 61 (30%) descended (became nonretractile), whereas 66 (32%) became UDTs during a mean followup of 2.8 years. A total of 77 testes (38%) had remained retractile at the most recent followup examination (fig. 1). Of the 62 retractile testes with a taut spermatic cord 35 (56%) became UDTs during a mean followup of 2.0 years. Among the 66 UDTs 5 orchiopexies had been scheduled but not yet performed at the time of data analysis. Of the 61 orchiopexies performed 8 (13%) demonstrated a hernial sac, and the remainder showed a fibrous remnant of the processus vaginalis. Of the 122 boys 37 continue to be followed and 13 have been lost to followup. Mean age at diagnosis in boys with development of UDTs was 4.9 years vs 6.6 years in those with development of descended (nonretractile) testes (p ⫽ 0.001). Retractile testes had a 58% chance of spontaneously descending in boys 7 years or older vs a 21% chance in boys younger than 7 (p ⫽ 0.00004, fig. 2). Likewise, retractile testes had a 19% chance of remaining retractile in boys 7 years or older vs a 44% chance in boys younger than 7 (p ⫽ 0.01). This difference was unlikely related to an effect of shorter followup in younger patients, since mean followup was 755 days in boys 7 years or older vs 1,118 days in those younger than 7 (p ⫽ 0.0004). Transition probabilities from a given initial state to a given final state or “resolution” during followup with corresponding 95% CIs are outlined in the table. Maximum followup was 8.5 years in patients with bilateral retractile
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FIG. 2. Rates of spontaneous descent and unchanged retractile testis, by age group
testes and 5.3 years in patients with 1 retractile testis. In boys with bilateral retractile testes the highest probability of resolution was 0.24 and corresponded to development of bilateral UDTs. For boys with 1 retractile testis and 1 descended testis at the onset of the study there was a higher probability that the retractile testis descended (69%) vs requiring intervention for UDT (32%, p ⬍0.05). For boys with 1 retractile testis and 1 undescended testis (or other conditions different from descended) at the onset of the study there was a higher probability that the retractile testis required intervention for UDT (66%). None of the patients in this group had the affected testis descend. However, the results for this latter group should be carefully considered due to the small number of patients in this situation. Median time to resolution for patients with unilateral or bilateral retractile testes was 3.0 years, compared to 2.6 years for those with the unaffected testis descended at onset and 2.3 years for those with the unaffected testis undescended at onset. DISCUSSION Higher mean age at orchiopexy and high rates of orchiopexy suggest that testicular ascent is a real phenomenon. Although physical examination error (misdiagnosis or failure to screen) can result in the failure to recognize a congenital UDT, it cannot account for all cases of testicular ascent. As
many as 2% of initially descended testicles undergo testicular ascent, with the highest incidence seen in boys with retractile testes.10 Although 32% of the retractile testes in our series became acquired UDTs, the risk of ascent in a retractile testis may be as high as 50%.10 Previously unrecognized low-lying congenital UDTs or ectopic testes that become more noticeable with somatic growth may account for the remainder of cases. We determined that a retractile testis with a tight (inelastic) spermatic cord ultimately became a UDT in 56% of cases. Consequently, boys with such testes, as well as testes that are tender with traction, should undergo careful followup surveillance, since the need for surgical intervention seems high. In fact, pain with traction of the spermatic cord and rapid retraction of the scrotum were among the criteria Wyllie used to distinguish low-lying UDTs from retractile testes.11 In addition, we identified a greater chance of a retractile testis undergoing spontaneous descent in boys 7 years or older. In fact, no boy older than 8.6 years had development of an acquired UDT, and all boys older than 10.2 exhibited spontaneous descent of the retractile testes. However, these results must be interpreted with caution, since the group of boys older than 8.6 years only numbered 15. Pathological studies also provide evidence that retractile testes may be abnormal. Han et al found that although
Cumulative transition probability for events Position (rt/lt) Initial
Final
Probability
Standard Error (95% CI)
Bilat retractile Bilat retractile Bilat retractile Bilat retractile Bilat retractile Bilat retractile Retractile/descended Retractile/descended Retractile/descended Retractile/undescended Retractile/undescended Retractile/undescended
Bilat retractile Retractile/undescended Retractile/descended Bilat undescended Bilat descended Undescended/descended Retractile/descended Undescended/descended Bilat descended Retractile/undescended Bilat undescended Descended/undescended
0.02 0.20 0.10 0.24 0.22 0.22 0 0.69* 0.32* 0.34 0.66 0
0.02 (0–0.06) 0.05 (0.10–0.29) 0.04 (0.03–0.17) 0.05 (0.14–0.35) 0.05 (0.12–0.33) 0.05 (0.11–0.32) 0 (0–0) 0.09 (0.50–0.87) 0.09 (0.13–0.50) 0.17 (0.02–0.67) 0.17 (0.33–0.98) 0 (0–0)
* Statistically significantly different at p ⫽ 0.05.
RETRACTILE TESTIS retractile testes have a significantly higher average number of spermatogonia than cryptorchid testes, they have the same degree of tubular degeneration, suggesting that retractile testes undergo some abnormal histological change.13 Further pathological evidence from the Children’s Hospital of Philadelphia suggests that once a previously retractile testis undergoes testicular ascent it acquires the same decrease in total and differential germ cell count as a primary undescended testis.14 Whether these changes are reversible following orchiopexy is unknown. The limitations of our study must be addressed. As a retrospective study, potential errors may have been introduced by patient selection, lack of randomization, lack of testicular biopsy, incomplete data acquisition and the fact that not all patients were followed through puberty. Some of our conclusions might be preliminary, due to the fact that 51 boys with retractile testes were not included in the analysis because they were only examined once. In addition, at the time of data analysis 38% of the patients still had a retractile testis at the most recent visit. Also, errors in physical examination could have occurred, delaying the diagnosis of UDT. However, this scenario seems unlikely, because patients were examined by a single pediatric urologist using a strict and consistent definition of retractile testis. Furthermore, none of the patients met any of the criteria set forth by Wyllie11 favoring an incompletely descended testis over a retractile testis. Although we did not specifically measure testicular volume, no appreciable difference in volume was noted on physical examination compared to the contralateral side when descended, or to expected volume for age when both sides were retractile. In addition, we did not biopsy the retractile testes at the time of orchiopexy to determine if any pathological changes had occurred. However, these changes are well documented in the literature. The optimal management of the retractile testis has not been delineated. However, our study suggests that regular physical examination is important. Determination of the appropriate management awaits the results of future prospective trials. Although we routinely perform orchiopexy on acquired undescended testes, the results of a recent longitudinal study suggest that the majority of these testes will undergo spontaneous descent during puberty and will have a volume appropriate for patient age.15 Whether fertility in these boys will be normal remains to be seen. Although some investigators have reported successful treatment with hormonal therapy, responses are variable between studies and are often not durable during the long term. Our study reveals that retractile testes are not a normal variant, since they have a considerable risk of undergoing ascent and lying outside the scrotum. In the first known longitudinal study on retractile testes Wyllie found that 42 of 100 retractile testes acquired a higher position.11 However, he did not comment on how many actually left the
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scrotum. To our knowledge our series is the first longitudinal study of retractile testes in the United States. We have demonstrated that retractile testes have a significant risk (32%) of becoming ascending testes unrelated to misdiagnosis or physical examination error. This risk is greater in boys younger than 7 years and in those with a tight (inelastic) spermatic cord. Boys with a retractile testis need to be monitored until the testis has descended.
Abbreviations and Acronyms UDT ⫽ undescended testis REFERENCES 1. Scorer, C. G. and Farrington, G. H.: Congenital Deformities of the Testis and Epididymis. New York: Appleton-CenturyCrofts, 1971 2. Chilvers, C., Pike, M. C., Forman, D., Fogelman, K. and Wadsworth, M. E.: Apparent doubling of frequency of undescended testis in England and Wales in 1962-81. Lancet, 2: 330, 1984 3. MacKellar, A., Lugg, M. M. and Keogh, E. J.: The undescended testis: lies, damned lies and statistics. Prog Reprod Biol Med, 10: 24, 1984 4. Campbell, D. M., Webb, J. A. and Hargreave, T. B.: Cryptorchidism in Scotland. Br Med J, 295: 1235, 1987 5. Tamhne, R. C., Jarvis, S. N. and Waterston, A. J.: Auditing community screening for undescended testes. Arch Dis Child, 65: 888, 1990 6. Jones, M. E., Swerdlow, A. J., Griffith, M. and Goldacre, M. J.: Prenatal risk factors for cryptorchidism: a record linkage study. Paediatr Perinat Epidemiol, 12: 383, 1998 7. Fenton, E. J. M., Woodward, A. A., Hudson, I. L. and Marschner, I.: The ascending testis. Pediatr Surg Int, 5: 6, 1990 8. Hack, W. W., Meijer, R. W., Van Der Voort-Doedens, L. M., Bos, S. D. and De Kok, M. E.: Previous testicular position in boys referred for an undescended testis: further explanation of the late orchidopexy enigma? BJU Int, 92: 293, 2003 9. Rabinowitz, R. and Hulbert, W. C., Jr.: Late presentation of cryptorchidism: the etiology of testicular re-ascent. J Urol, 157: 1892, 1997 10. Barthold, J. S. and Gonzalez, R.: The epidemiology of congenital cryptorchidism, testicular ascent and orchiopexy. J Urol, 170: 2396, 2003 11. Wyllie, G. G.: The retractile testis. Med J Aust, 140: 403, 1984 12. Aalen, O. O., Borgan, O. and Fekjaer, H.: Covariate adjustment of event histories estimated from Markov chains: the additive approach. Biometrics, 57: 993, 2001 13. Han, S. W., Lee, T., Kim, J. H., Choi, S. K., Cho, N. H. and Han, J. Y.: Pathological difference between retractile and cryptorchid testes. J Urol, 162: 878, 1999 14. Rusnack, S. L., Wu, S.-Y., Huff, D. S., Snyder, H. M., III, Zderic, S. A., Carr, M. C. et al: The ascending testis and the testis undescended since birth share the same histopathology. J Urol, 168: 2590, 2002 15. Hack, W. W., Meijer, R. W., van der Voort-Doedens, L. M., Bos, S. D. and Haasnoot, K.: Natural course of acquired undescended testis in boys. Br J Surg, 90: 728, 2003
