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| Figure 1. Female ectopic testicle. |
Figure 2. Location of cryptorchid and ectopic testes. |
Mark A. Barraza, M.D. is a Pediatric Urologist with the Department of Surgery , Division of Pediatric Urology at Nemours Children's Clinic.
In normal embryologic development maleness is determined by the presence of HY antigen located on the Y chromosome. In the absence of the HY antigen, the femaleness will develop.
Gonadal development occurs during the first 3 weeks of embryologic development. The transformation of gonalda-blastema into testicular chords is controlled by a gene on the short arm of the Y chromosome. By the eighth week the tunica albugenia surrounding the fetal testis and the gubernacula are more present. During the tenth week of development fetal testosterone produced by the fetal testis causes elongation of the phallus. The urogenital groove fuses to form the urethra and median raphe of the penis. The bilateral genital swellings become scrotal swellings, which fuse to form the scrotal septum and scrotal raphe. By the fourteenth week the penile shaft continues to elongate and the urethra has fused to level of the glans. The glanular urethra forms from an invagination at the tip of the glans and proceeds proximally to meet the fused urogenital groove. At this point in development, the penis is curved ventrally. The prepuce develops as a fold of tissue that grows distally and is complete at five months gestation. The prepuce fuses to the glans then reseparates from it under the influence of testosterone. This process of separation is incomplete at birth and continues for several years thereafter. By twenty-eight weeks the processus vaginalis, an outpouching of the abdominal peritoneum, has herniated through the abdominal wall and descended in the inguinal canal. The testis then descends through the inguinal canal into the scrotum following the gubernaculum and processus vaginalis. Anomalies of the genital organs are frequent and are the result of an abnormality at some state of embryologic development. The more common anomalies include hypospadias, cryptorchidism, inguinal hernias and hydroceles and a variety of penile and scrotal abnormalities.
The most common anomaly in the male genital tract is cryptorchidism. Maternal HCG stimulates the fetal testis to secrete testosterone which influences testicular development and descent. The normal male with descended testes demonstrates a transient increase in testosterone at sixty days after birth. This testosterone response seems to be blunted in children with undescended testes. Many other factors both hormonal and mechanical can result in undescended testes. Subsequent fertility and testicular tumor formation are the most common problems related to cryptorchid testes.
Undescended testes may be truly cryptorchid or ectopic. Cryptorchid testes may be an abdominal, inguinal or suprascrotal position. Ectopic testes can assume any position outside of the inguinal canal (Figures1 and 2). Three percent of term infants and thirty three percent of premature babies will have a cryptorchid testis. Virtually all testes that eventually descend will do so by six months of age, therefore, children with undescended testes after six to eight months of age should be considered for surgical correction. HCG stimulation is usually reserved for bilateral undescended testes. Even though it may not result in complete descent, subsequent orchidopexy is often technically easier after hormonal manipulation. Laparoscopy as both a diagnostic and therapeutic tool is being utilized more often especially in cases of non-palpable testes.
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| Figure 1. Female ectopic testicle. |
Figure 2. Location of cryptorchid and ectopic testes. |
Retractile testes result from hyperactivity of the cremaster muscle that causes retraction of the testicle into the inguinal canal. On examination with gentle manipulation the affected testis can be manipulated into its respective hemiscrotum where it will remain when the cremaster muscle is relaxed. Testicular development and maturation is normal and surgical intervention is not indicated. Children with retractile testes should have a yearly examination until the age of puberty at which time the cremaster reflex lessens and the testes assume their normal scrotal position.
An ascending testicle has been described recently in which a previously documented descended scrotal testis later comes into an extrascrotal position. This is a result of a delayed resorption of the processus vaginalis and a "pulling up" of the testicle. The affected testis feels tethered and cannot be manipulated into a dependent scrotal position. Ninety-eight percent of ascended testes are associated with a patent processus vaginalis and, therefore, a potential inguinal hernia and surgical correction is necessary.
A vanished testis describes the child with a nonpalpable undescended testicle who upon examination may have a small hard pea sized structure in the affected hemiscrotum which represents an atrophic calcified testicular remnant. This condition is most often related to a neonatal or prenatal testicular torsion or other early vascular accident with subsequent testicular atrophy (Figure 3). Treatment includes surgical exploration and excision of the testicular remnant. Often laparoscopy is used to search for an intraabdominal testis and at laparoscopy a blind ending spermatic vessel and vas deferens can be seen entering the internal inguinal ring.
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Figure 3. Vanished Testis |
Hypospadias is a common anomaly occurring in one in two hundred and fifty male children. The exact etiology of hypospadias is unknown; however, worldwide the incidence of hypospadias seems to be increasing. Environmental pollutants with estrogen like affects have been implicated, but not proven in the cause of hypospadias.
Hypospadias occurs as a result of incomplete fusion of the urethral groove producing a urethral meatus located in an aberrant location on the ventral surface of the penis. The meatus can be located anywhere along the ventral penile shaft from the meatus distally to the perineum in the most severe cases of proximal hypospadias. Typically, the corpus spongiosusm is absent or poorly developed surround the hypospadiac urethra. Chordee, or ventral curvature of the penis is a commonly associated finding and should be described as mild moderate or severe.
Hypospadias is best classified according to the location of the urethral meatus: 1) glanular; 2) coronal; 3) distal (Figure 4), mid or proximal shaft (Figure 5); 4) scrotal (Figure 6); or 5) perineal. Coronal and glanular defects account of over 85% of cases hypospadias, whereas perineal hypospadias is present in only two to three percent of children with this anomaly. There does not seem to be a significant increase in the incidence of urinary tract anomalies in children with hypospadias, therefore, routine screening with an IVP or ultrasonography and voiding cysto-urethrography are generally not indicated unless urinary infections are present.
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Figure 4. Distal
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Figure 5. Proximal
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Figure 6. Scrotal
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Most cases of hypospadias should be surgically corrected with the goal of producing a straight penis with the meatus at the tip of the glans and a cosmetically pleasing appearance. Even severe degrees of hypospadias can usually be repaired in a one staged procedure on an outpatient basis. The optimal age for correction is between six and twelve months of age.
The retractile or concealed penis is most often noted in young boys after circumcision. The penis rather than protruding normally tend to retract beneath the prepubic fat pad resulting in an uncircumcised appearance. Parents often comment on the "lousy job" done by the circumcising physician. In fact, however, this condition has little to do with the technique of the circumcision, but rather relates to the presence of dysgenetic bands of tissue in the dartose layer of fascia that act as "rubber bands" to retract the penis proximally. Surgical correction requires division of these dysgenetic bands in severe cases (Figures 7 and 8). Less severe cases of penile retraction may actually improve at the time of puberty.
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Figure 7 and Figure 8. Preop concealed penis. |
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Penile cysts can occur anywhere along the penile or scrotal raphe. They are usually asymptomatic, but can get secondarily infected. Cysts are due to entrapment of epithelial cells during fusion of the labial scrotal folds. Epidermal inclusion cysts, sebaceous cysts and mucoid urethral cyst also can occur (Figure 9). In uncircumcised boys entrapped squamous debris between the inner prepuce and glans can accumulate and is often misconstrued as a cyst. The "infantile smegma" will eventually work its way to the surface and gently separate the prepucial-glanular adhesions. No treatment is necessary for this infantile smegma and forcible separation of the prepucial adhesions from the glans should be discouraged.
Penoscrotal webbing describes a fusion of the ventral penile and scrotal skin resulting in a loss of the penoscrotal angle (Figure 10). The penis has a "volcano" appearance and is usually associated with a significantly tight phimosis. Neonatal circumcision is contraindicated and correction should be undertaken at six to eight months of age.
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Figure 9. Urethral Cyst |
Figure 10. Webbed penis. |
The presence of ectopic scrotal tissue is very uncommon and usually occurs in the presence of severe colloquial extrophy. Occasionally ectopic scrotal tissue can be found in a child with otherwise normal genitalia. The ectopic scrotal tissue is usually located in the inner thigh or near the external inguinal ring. Typically the ipsilateral testicle lies within the ectopic scrotum (Figure 11). Surgery involves either transposition or excision of ectopic scrotal tissue with placement of the testicle in a normal scrotal position.
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Figure 11. Ectopic
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Figure 12. Penoscrotal
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Penoscrotal transposition is an anomaly frequently associated with severe hypospadias. The penis lies entirely behind the scrotum in complete transposition (Figure 12). In less severe forms, the penis may appear to arise from center of the scrotum or be enveloped by the scrotum. Correction of penoscrotal transposition is usually carried out at the time of hypospadias repair either as a single stage or in multi-staged procedures.
Congenital hydroceles are a very common finding in newborn male children. There are two classifications of hydroceles based upon whether or not the processus vaginalis is patent. Noncommunicating hydroceles represent fluid contained within the tunica vaginalis surrounding the testis after the processus vaginalis has obliterated. Simple noncommunicating hydroceles are very common at birth and usually resolve within the first year of life. Hydroceles that persist after one year of age usually do not resolve and surgical correction is indicated (Figure 13).
Communicating hydroceles represent fluid within the tunica vaginalis associated with a patent processus vaginalis. Communicating hydroceles often fluctuate in size depending upon the gravitational flow of fluid between the abdominal cavity and tunica vaginalis surrounding the testis. These hydroceles typically will enlarge in the evening when the child is supine at night the hydrocele may appear to resolve. Communicating hydroceles that are present after six months of age should be surgically corrected.
Inguinal hernias represent the presence of intraabdominal content that has protruded through the patent processus vaginalis into the inguinal canal and potentially into the scrotum (Figure 14). Inguinal hernias are more common in premature infants and are present in up to three percent of the general population. Because of the potential of incarceration of bowel or injury to the vascular supply to the testis, inguinal hernias should be surgically corrected on an elective basis sometime after diagnosis is made.
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