Anomalies of the Penis and Urethra

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Chapter 538 Anomalies of the Penis and Urethra

Jack S. Elder

Hypospadias

Hypospadias, a urethral opening that is on the ventral surface of the penile shaft, affects 1/250 male newborns, and its incidence may be increasing. Usually it is an isolated defect, but its incidence is increased in disorders of sexual differentiation (intersex), anorectal malformation, and congenital heart disease. Typically, there is incomplete development of the prepuce, called a dorsal hood, in which the foreskin is on the sides and dorsal aspect of the penile shaft and deficient or absent ventrally. Some boys with hypospadias, particularly those with proximal hypospadias, have chordee, in which there is ventral penile curvature during erection. It has been speculated that the incidence of hypospadias appears to be increasing, possibly because of in utero exposure to estrogenic or antiandrogenic endocrine-disrupting chemicals (e.g., polychlorobiphenyls, phytoestrogens).

Clinical Manifestations

Hypospadias is classified according to the position of the urethral meatus after taking into account whether chordee is present (Fig. 538-1). The deformity is described as glanular (on the glans penis), coronal, subcoronal, midpenile, penoscrotal, scrotal, or perineal. Approximately 60% of cases are distal, 25% are subcoronal or midpenile, and 15% are proximal. In the most severe cases, the scrotum is bifid and sometimes there is moderate penoscrotal transposition. As many as 15% of affected boys have a megameatal variant, in which the foreskin is developed normally (megameatus intact prepuce [MIP] variant), and there is either glanular or subcoronal hypospadias with a “fish mouth” meatus. These cases might not be diagnosed until after a circumcision is performed.

Figure 538-1 Varying forms of hypospadias. A, Glanular hypospadias. B, Subcoronal hypospadias. Note the dorsal hood of foreskin. C, Penoscrotal hypospadias with chordee. D, Perineal hypospadias with chordee and partial penoscrotal transposition. E, Megameatal variant of hypospadias diagnosed following circumcision; note absence of hooded foreskin. F, Complete penoscrotal transposition with scrotal hypospadias.

Approximately 10% of boys with hypospadias have an undescended testis; inguinal hernias also are common. In the newborn, the differential diagnosis of proximal hypospadias associated with an undescended testis should include forms of a disorder of sexual differentiation, particularly female virilization (congenital adrenal hyperplasia), mixed gonadal dysgenesis, partial androgen insensitivity, and true hermaphroditism. A karyotype should be obtained in patients with midpenile or proximal hypospadias and cryptorchidism (Chapter 577). In boys with penoscrotal hypospadias, a voiding cystourethrogram should be considered because 5-10% of these children have a dilated prostatic utricle, which is a remnant of the müllerian system (Chapter 548). The incidence of upper urinary tract abnormalities is low unless there are abnormalities of other organ systems.

Complications of untreated hypospadias include deformity of the urinary stream, typically ventral deflection or severe splaying; sexual dysfunction secondary to penile curvature; infertility if the urethral meatus is proximal; meatal stenosis (congenital), which is uncommon; and cosmetic appearance. The goal of hypospadias surgery is to correct the functional and cosmetic deformities. Whereas hypospadias repair is recommended for all boys with midpenile and proximal hypospadias, some boys with distal hypospadias have no functional abnormality and do not need any surgical correction.

Treatment

Management begins in the newborn period. Circumcision should be avoided, because the foreskin often is used in the repair in most cases. The ideal age for repair in a healthy infant is 6-12 mo, because the risk of general anesthesia at this age is similar to older children; penile growth over the next several years is slow; the child does not remember the surgical procedure; and postoperative analgesic needs are less than in older children. With the exception of proximal hypospadias, virtually all cases are repaired in a single operation on an ambulatory basis. The most common repair involves tubularization of the urethral plate distal to the urethral meatus, with coverage by a vascularized flap from the foreskin, termed a tubularized incised plate (TIP) repair. More proximal cases might require a 2-stage repair. The complication rate is low: 5% for distal hypospadias, 10% for midpenile hypospadias, and 15-20% for proximal hypospadias. The most common complications include urethrocutaneous fistula and meatal stenosis. Other complications include a deformed urinary stream, persistent penile curvature, and dehiscence of the hypospadias repair. Treatment of these complications generally is straightforward. In complex cases a buccal mucosa graft is used to create urethral mucosa. Repair of hypospadias is a technically demanding operation and should be performed by a surgeon with specialty training in pediatric urology and extensive experience.

Chordee without Hypospadias

In some boys there is mild or moderate ventral penile curvature (chordee) and incomplete development of the foreskin (dorsal hood), but the urethral meatus is at the tip of the glans (Fig. 538-2). In most of these boys, the urethra is normal but there is insufficient ventral penile skin or prominent, inelastic ventral bands of dartos fascia that prevent a straight erection. In some cases, the urethra is hypoplastic, and a formal urethroplasty is necessary for repair. The only sign of this anomaly in the neonate may be the hooded foreskin, and delayed repair under general anesthesia at 6 mo of age is recommended.

Figure 538-2 A and B, Two examples of chordee without hypospadias. Note hooded foreskin and normal location of urethral meatus.

Phimosis and Paraphimosis

Phimosis refers to the inability to retract the prepuce. At birth, phimosis is physiologic. Over time, the adhesions between the prepuce and glans lyse and the distal phimotic ring loosens. In 90% of uncircumcised boys the prepuce becomes fully retractable by 3 yr of age. Accumulation of epithelial debris under the infant’s prepuce is physiologic and does not mandate circumcision. In older boys, phimosis may be physiologic, may be pathologic from inflammation and scarring at the tip of the foreskin (Fig. 538-3), or occurs after circumcision. The prepuce might have been retracted forcefully on 1 or 2 occasions in the past, which can result in a cicatricial scar that prevents subsequent retraction of the foreskin. In boys with persistent physiologic or pathologic phimosis, application of corticosteroid cream to the foreskin 3 times daily for 1 mo loosens the phimotic ring in 2/3 of cases. If there is ballooning of the foreskin during voiding or phimosis beyond 10 yr of age and topical corticosteroid therapy is ineffective, circumcision is recommended.

Figure 538-3 Balanitis xerotica obliterans. Note whitish cicatricial plaque.

Paraphimosis occurs when the foreskin is retracted past the coronal sulcus and the prepuce cannot be pulled back over the glans (Fig. 538-4). Painful venous stasis in the retracted foreskin results, with edema leading to severe pain and inability to reduce the foreskin (pull it back over the glans). Treatment includes lubricating the foreskin and glans and then simultaneously compressing the glans and placing distal traction on the foreskin to try to push the phimotic ring past the coronal sulcus. In rare cases, emergency circumcision under general anesthesia is necessary.