External Genital Anomalies in Boys

Normal Male External Genitalia

• Embryology
  • At 9-13 weeks of gestation, dihydrotestosterone (DHT) simulates androgen receptors the
    1. Genital tubercle to differentiate into penis
    2. Urethral folds to differentiate into the corpus spongiosum/penile shaft
    3. Labioscrotal swellings to differentiate into scrotum
       • Also known as genital swellings or labioscrotal folds§
    4. The male develops in a proximal-to-distal manner
    5. As the penis forms from the elongation and enlargement of the phallus, the lateral walls of the urethral groove form from the ventrally located urethral folds, which then fuse in the midline.
    6. The scrotum forms from midline fusion of the labioscrotal swellings as delineated by the scrotal raphe.
  • By the end of the first trimester (12 weeks), the external genitalia are completely masculinized
    • US sex determination after 13 weeks is accurate in 99-100% of cases of gestation without malformed external genitalia
  • In females and males with abnormalities in testosterone and/or DHT production, 5α-reductase deficiency, or androgen-receptor insufficiency, the
    1. Genital tubercle passively become the clitoris
    2. Urethral folds passively become the labia minora
    3. Labioscrotal swellings passively become the labia majora
• See Table 146-3: Tanner Classification of Sexual Maturity Stages in Boys

Penile Anomalies

Prepuce (Foreskin)

Phimosis

• See CUA Circumcision Guidelines

Paraphimosis

• In most cases, manual compression of the glans with placement of distal traction on the edematous foreskin allows reduction of the paraphimotic ring
• Insert figure
• Other options include:
  1. Application of an iced glove for 5 minutes
  2. Application of granulated sugar for 1-2 hours
  3. Placement of multiple punctures in the edematous skin

Circumcision

• See CUA Circumcision Guidelines
• Potential benefits:
  1. Reduced risk of Penile cancer
  2. Reduced risk of UTIs
  3. Reduced risk of Sexually transmitted diseases including HIV
  4. Reduced risk of Phimosis
  5. Reduced risk of Balanitis
• Contraindications (2):
  1. Neonates with other penile conditions (hypospadias, penile curvature, dorsal hood deformity, buried penis, and webbed penis) that require surgical correction
     • Other conditions commonly seen in neonates that should be taken into consideration are a large hydrocele or inguinal hernias, which are more likely to develop secondary phimosis, buried penis, and trapped penis.
     • There should be complete separation of the prepuce from the glans and complete inspection of the meatus and the corona to confirm the absence of anomalies, including hypospadias.
  2. Coagulopathy
• Techniques and devices for neonatal circumcision:
  1. Gomco clamp
  2. Mogen clamp
  3. Plastibell device
• Complications (6):
  • Risk of complications after circumcision: 0.2-5%
  1. Bleeding
     • Most common complication, occurs in 0.1% and is more common in older children
     • Usually localized from the frenulum
  2. Wound infection
     • Rare complication
     • Antibiotic ointment (e.g., bacitracin) after circumcision usually prevents its development
  3. Penile skin complications
     • Insufficient or asymmetrical excision can result in a cosmetic and social dilemma for the parents and child
     • Excessive skin excision can result in:
       1. Penile chordee, torsion, and lateral deviation
       2. Trapped penis from a cicatricial scar
  4. Glanular adhesions and skin bridges
     • Glanular adhesions and skin bridges, attachments of the glans and penile shaft, respectively, are common complications
     • Both can occur in the well-circumcised penis and are usually the result of the physiologic retraction of the penis caused by a suprapubic fat pad and diaper irritation of the penis
     • Management
       • Persistent adhesions can be lysed in the office with the application of a topical analgesic such as EMLA cream
       • Low-dose corticosteroids have been relatively unsuccessful in lysing adhesions
  5. Meatal Stenosis
     • The normal urethral meatus is:
       • Age<4: 10 Fr
       • Age 4-10: 12 Fr
       • Age>10: 14 Fr
     • Symptoms include:
       1. Narrow, high-velocity stream
       2. Urinary stream deviation, typically in an upward direction resulting from a meatal baffle or ventral web located at the inferior aspect of the meatus
       3. Penile pain at the initiation of micturition
  6. Penile Trauma
     • Most serious complication
     • Includes urethral injury, excision of the glans and/or penile shaft, and penile necrosis
       • Urethral injury requires urethroplasty
       • Excision of the glans can be repaired by suturing the excised tissue back to the penis, often without the need for microscopic repair
         • Good results if performed within 8 hours

Lichen sclerosis (Balanitis Xerotica Obliterans)

• See Penis and Urethra Surgery Chapter Notes
• Rare in children age <5 years
• At puberty, inability to retract the prepuce is the most common presentation
• Other presenting symptoms include:
  • Local infection
  • Irritation
  • Discomfort after micturition
  • Bleeding
  • Occasionally acute urinary retention or urinary incontinence
• Circumcision is the preferred treatment along with meatotomy or meatoplasty if there is meatal involvement
  • Children with meatal involvement should be observed post-operatively because of the risk of recurrent meatal stenosis
  • The use of topical corticosteroids has had limited benefit to treat mild BXO of the prepuce with minimal scar formation

Abnormal Penile Number

Aphallia

• Penile agenesis results from failure of development of the genital tubercle
• The karyotype almost always is 46,XY, and the usual appearance is that of a well-developed scrotum with descended testes and an absent penile shaft.
• Associated malformations are common and include cryptorchidism, vesicoureteral reflux, horseshoe kidney, renal agenesis, imperforate anus, and musculoskeletal and cardiopulmonary abnormalities
• Testing should include a karyotype and other appropriate studies to detect associated malformations of the urinary tract or other organ systems.
  • MRI may be beneficial in determining the severity of the defect

Diphallia

• Duplication of the penis is a rare anomaly; incidence of 1 in 5 million live births

Abnormal penile size

• Normal penile size in a full-term male neonate
  • Stretched length: 3.5cm (13.3cm in adults)
  • Diameter: 1.1cm

Inconspicuous Penis

• Definition of inconspicuous penis: penis that appears to be small but with normal stretched penile length measured from the pubic symphysis to the tip of the glans and normal diameter of the penile shaft
  • Differentiated from micropenis, in which the penis is abnormally small
• Subtypes (3): buried penis, webbed penis, and trapped penis
  • Buried Penis
    • Definition of a buried penis: a normally developed penis that is hidden away by a suprapubic fat pad
    • Classified into 3 categories based on cause of the concealment:
      1. Poor penopubic fixation of the skin at the base of the penis
      2. Obesity
      3. A trapped penis from cicatricial scarring after penile surgery, typically a circumcision
         • May occur after neonatal circumcision in an infant with significant scrotal swelling as a result of a hernia or hydrocele or after routine circumcision in an infant with a webbed penis
    • Insert figure
    • Management
      • Based on the cause
      • The trapped penis can be managed with betamethasone, vertical relaxation incision, and formal repair
  • Webbed Penis
    • Definition of a webbed penis: a congenital or acquired condition resulting from the scrotal skin extending onto the ventrum of the penis
    • Also known as penoscrotal fusion

Micropenis

• Definition of micropenis: a normally formed penis that is at least 2.5 standard deviations (SD) below the mean size in stretched length for age
  • Stretched penile length correlates more closely with erectile length than does the relaxed penile length and should be compared with standards for penile length
  • Micropenis in the full-term neonate is stretched penile length <1.9 cm long
• Causes
  • See CW11 Box 146-1: Etiology of Micropenis
  • Results from a hormonal abnormality that occurs after 14 weeks of gestation
  • Hypogonadotropic hypogonadism (most common cause)
    • Failure of the hypothalamus to produce adequate quantities of gonadotropin-releasing hormone (GnRH) can occur in Prader-Willi syndrome, Kallmann syndrome (genital-olfactory dysplasia), Laurence-Moon-Biedl syndrome, and the CHARGE association
  • Hypergonadotropic hypogonadism (primary testicular failure)
  • Idiopathic
  • Often associated with major chromosomal defects, including: Klinefelter syndrome (47,XXY) and other X polysomy syndromes, deletions, translocations, and trisomy involving chromosomes 8, 13, and 18
• Initial evaluation of a child with micropenis includes a history, physical examination, and a karyotype at birth.
• The ratio of the length of the penile shaft to its circumference is usually normal, but occasionally the corpora cavernosa are severely hypoplastic. The testes are usually small and frequently cryptorchid, whereas the scrotum is usually fused and often diminutive
• Although ultimate penile size may be below the normal range, men born with micropenis have male gender identity and most have satisfactory sexual function

Abnormal Penile Orientation

Congenital penile curvature

• Referred to as chordee
• Results from disproportionate development of the tunica albuginea of the corporal bodies
  • Not associated with urethral malformation§
• Most commonly in the ventral direction (as opposed to Peyronie’s which is dorsal curvature), with preserved penile length and typically normal erectile function and rigidity§
• Commonly associated with hypospadias
  • Isolated chordee may occur with or without a dorsal hood of prepuce and is commonly associated with a deficiency of the ventral skin
• Congenital dorsal penile curvature may be an isolated condition with or without asymmetrical penile skin or associated with epispadias and a ventral hood of prepuce.
• Healthy young men usually present between age 18-30 when the abnormal curvature is brought to their attention from their sexual partner
• Treatment is surgical and is offered to patients whose congenital penile curvatures significantly interferes with satisfactory sexual relations of the patient or partner.
  • Plication is used almost exclusively§

Penile Torsion

• Definition of penile torsion: a rotational deformity of the penile shaft, usually in the counterclockwise direction
• The cause has not been clearly delineated but may be the result of an anomalous arrangement of penile shaft skin.

Penile Masses (5):

1. Penile cysts
   • Most common penile mass in children
   • Can be congenital or acquired
2. Parameatal Urethral Cyst
   • A rare anomaly and appears as a small blister in proximity to the urethral meatus
3. Inclusion Cysts
   • Smegma pearl
     • Smegma, produced under the foreskin, is made of 27% fat and 13% protein§
     • A smegma pearl is a type of inclusion cyst where smegma becomes entrapped under the unretractable foreskin
       • See Figure
     • Most common acquired cystic lesion of the penis
   • May form after penile surgery, including circumcision and hypospadias repair, owing to islands of epithelium within the subcutaneous tissue. Excision of the epidermal inclusion is recommended.
4. Congenital Penile Nevi
   • Pigmented lesions that can form on the glans and penile shaft tend to be superficial and benign and should be excised
5. Juvenile Xanthogranuloma
   • Uncommon benign lesion of the penis
   • Lesions appear as solitary or multiple pigmented (yellow, orange, gold, brown, or red) nodules of rapid onset. They measure 2-20 mm in diameter and are well demarcated, firm, and rubbery.
   • Predominantly seen in infancy or early childhood.
   • The lesion is often self-limited, and a period of 1 year of expectant monitoring is advised to avoid potentially unnecessary ablative genital surgery

Accessory Urethral Openings

• Congenital Urethral Fistula
• Urethral Duplication
  • Duplication most commonly occurs in the sagittal plane with one urethra located ventrally and the other dorsally
    • Usually the dorsal urethra is considered the accessory urethra with or without a urinary stream, whereas the ventral urethra carries the urine stream and the anatomic landmarks such as the external sphincter and verumontanum.
  • Associated genitourinary, gastrointestinal, and musculoskeletal anomalies may be present
    • Vesicoureteral reflux is the most common associated anomaly
    • Other anomalies include renal agenesis, bilateral cryptorchidism, sacral agenesis, imperforate anus, radial hypoplasia, tracheoesophageal fistula, and other midline defects such as duplicated bladder, duplicated colon, imperforate anus and anorectal agenesis, bifid glans, thoracic hemivertebrae, and partial sacral agenesis
  • The most common presentation of urethral duplication is a double meatus and double urinary stream
  • Evaluation should include a voiding cystourethrogram, retrograde urethrogram, and direct visualization of the anatomy during cystourethroscopy

Genital Lymphedema

• A disfiguring disorder characterized by impaired lymphatic drainage that causes progressive penile or scrotal swelling
• Can be congenital or acquired

Priapism

• Stuttering, low-flow, high-flow priapism
  • See Priapism Chapter Notes
• Spontaneously resolving priapism
  • Form observed in neonates
  • Causes may include idiopathic factors, birth trauma, and polycythemia
  • No intervention is necessary because the priapism usually resolves in 2-6 days without adverse results

Penoscrotal Transposition (Scrotal Engulfment)

• Frequently occurs in conjunction with perineal, scrotal, or penoscrotal hypospadias with chordee
• Also associated with caudal regression, sex chromosome abnormalities, and Aarskog syndrome.
• As many as 75% of patients with complete penoscrotal transposition and a normal scrotum have a significant urinary tract abnormality, including renal agenesis and dysplasia, and other nongenitourinary anomalies

Scrotal Anomalies

• Bifid Scrotum
  • Deformity in which the labioscrotal folds are completely separated and without a median raphe
  • Most often associated with proximal hypospadias
• Ectopic Scrotum
  • The anomalous position of one hemiscrotum along the inguinal canal
    • Possible locations: suprainguinal (most common), infrainguinal, or perineal
  • Rare condition
  • Associated with cryptorchidism, inguinal hernia, bladder exstrophy, popliteal pterygium syndrome
  • Patients should undergo upper urinary tract imaging with US
• Scrotal Hypoplasia
  • Underdevelopment of one or both sides of the scrotum
  • Occurs most commonly in boys with an undescended testis
• Scrotal Agenesis
• Scrotoschisis
  • See Figure
  • When scrotoschisis is detected the clinician should suspect meconium peritonitis  
  • Treatment involves scrotal exploration with orchiopexy and primary closure of the scrotal wall defect

Vascular Lesions of the Genitalia

• Congenital Cutaneous Hemangiomas
  • Although the lesions may undergo a period of rapid growth lasting 3 to 6 months, gradual involution is common, and most lesions require no treatment
• Subcutaneous/Cavernous Hemangiomas
  • In contrast to cutaneous hemangiomas, which tend to involute, cavernous hemangiomas tend to enlarge gradually and should be treated with care.
  • Definitive treatment by en bloc resection is advised

Hernia and Hydroceles

Embryology

• The processus vaginalis forms during the 3rd month of gestation as the peritoneum bulges into the inguinal canal just before the onset of testicular descent.
  • On completion of testicular descent, the processus vaginalis obliterates and the portion adjacent to the testes becomes the tunica vaginalis
  • Obliteration of the processus vaginalis continues post-natally, and its failure to obliterate accounts for nearly all inguinoscrotal abnormalities seen in infancy and childhood
• Patent process vaginalis is associated with (4):
  1. Transverse testicular ectopia
  2. Epididymal anomalies
  3. Cryptorchidism
  4. Polyorchidism
  • Risk of spermatic cord torsion is associated with abnormal development of the tunica vaginalis but not patency of the processus vaginalis
• Incidence of incidental patency observed in older children and adults at autopsy or laparoscopy is ≈20%

Definitions

• Indirect inguinal hernia: a widely patent processus vaginalis extending beyond the internal inguinal ring containing abdominal contents (bowel, omentum, gonads) which may pass into the inguinal canal, labia, or scrotum
• Communicating hydrocele: a patent processus vaginalis extending beyond the internal inguinal ring containing peritoneal fluid alone, which extends to the testis, with fluid within the tunica vaginalis
• Hydrocele of the spermatic cord: fluid contained within a segment of patent processus vaginalis with obliterated processus distally and proximally
• Scrotal hydrocele: fluid contained within the tunica vaginalis surrounding the testis without communication proximally
  • May be seen as a chronic or acute scrotal swelling after an inflammatory, infectious, or traumatic event. The hydrocele size is typically stable but may decrease over time.
• Abdominoscrotal hydrocele: a large scrotal hydrocele that extends proximally across the internal inguinal ring into the abdomen without communication with the peritoneum
  • Associated with (4):
    1. A closed processus vaginalis.
    2. Testicular dysmorphism.
    3. Hydronephrosis.
    4. Increased pressure within the tunica vaginalis.

Epidemiology and Pathogenesis

• Inguinal Hernia and Communicating Hydrocele
  • Inguinal hernias develop in 1-5% of children, 5-10x more common in boys and significantly more common among premature infants
  • More common (3:1) on the right side
    • Attributed to the later descent of the right testicle
  • Risk factors for bilateral involvement (4):
    1. Female gender
    2. Prematurity
    3. Age < 1
    4. History of cryptorchidism
  • Average age at presentation is 3-4 years
  • The majority of new hydroceles occurring after birth and before puberty are associated with a patent processus vaginalis (clinically communicating, clear history of fluctuation)
• Noncommunicating Hydroceles
  • Hydroceles that spontaneously resolve during infancy or appear during or after puberty are more commonly non-communicating
  • These form from delayed fluid absorption or abnormal fluid dynamics within the tunica vaginalis

Diagnosis and Evaluation

• History and Physical Exam
  • History
    • Typically manifests as a painless bulge found in the groin or extending along the cord to the scrotum.
      • The bulge may be present only during periods of increased intra-abdominal pressure (crying or bowel movements
        • The presence of an intermittent bulge helps to distinguish a reducible inguinal hernia and communicating hydrocele from a scrotal hydrocele or hydrocele of the spermatic cord.
        • The child with an incarcerated inguinal hernia will be irritable or inconsolable and have a persistent or larger bulge without spontaneous reduction and may have decreased appetite and signs of bowel obstruction (abdominal distention, vomiting, and lack of flatus or stool)
  • Physical Exam
    • The supine position facilitates reduction of peritoneal fluid and intra-abdominal contents
    • The hydrocele fluid surrounding the testicle should transilluminate; however, neonatal bowel may also transilluminate.
    • The hydrocele of the spermatic cord is usually painless and variable in size. It may be confused for the testis because of its round-oval shape
• Imaging
  • Often of limited use

Management

• Hydroceles
  • Both communicating and non-communicating hydroceles may resolve spontaneously in infants (CW12 p392 and CW11)
    • No indication for surgery within the first 24 months of age
      • Indications for intervention:
        • Hydrocele associated with inguinal hernia
        • Hydrocele develops when child is several years old
        • Hydrocele enlarges during the period of observation
• Inguinal Hernia
  • Require surgical repair shortly after diagnosis, given the significant risk of associated complications
  • Standard Inguinal Hernia Repair
    • The traditional surgical approach to repairing an indirect inguinal hernia or communicating hydrocele is high ligation of the hernia sac at the level of the internal inguinal ring. This carries a high success rate
    • In peripubertal boys with hydrocele, determine if hydrocele is communicating or scrotal.
      • If communicating, inguinal approach is preferred
      • If scrotal, trans-scrotal hydrocele approach is performed as in adults and an inguinal incision made only if a proximal communication is identified.
    • Complications
      • Early postoperative complications, including bleeding and infection, are rare after standard hernia repair
      • Recurrent inguinal hernia
        • Rate after uncomplicated open repair: 0.5-1%
        • Causes include failure to properly identify or ligate the sac during the original procedure; a tear in the sac, leaving a strip of peritoneum along the cord; damage to the floor; or a missed direct hernia at the original exploration.
        • Laparoscopic inguinal hernia repair associated with higher risk of recurrence (up to 4%) than with open repair
      • Secondary cryptorchidism, testicular atrophy, and vasal injury is not well defined.
        • If a testis is incompletely descended or retractile, orchidopexy should be performed at the time of herniorrhaphy
  • Assessment of the contralateral internal ring
    • The need to assess the patency of the contralateral processus vaginalis or of the internal inguinal ring in children with a unilateral hernia remains controversial

Varicocele

• See Varicocele Chapter Notes

Epididymal cysts

• Simple cystic structures that may be palpable by the patient or examining physician or found incidentally by US
• Pathophysiology is unknown but may be related to an altered hormonal environment because they are linked to diethylstilbestrol (DES) exposure
• Management
  • Many resolve spontaneously; surgical intervention is rarely needed

Vasal Anomalies

• Congenital absence of the vas deferens (CAVD) is in most cases associated with specific mutations of the cystic fibrosis gene CFTR (cystic fibrosis transmembrane regulator) that are less severe than those encountered in patients with cystic fibrosis.
  • Disease can be bilateral (CBAVD) or unilateral (CUAVD) with a normal or obstructed contralateral vas
  • May be associated with renal agenesis or ectopia and/or partial or complete agenesis of the epididymis and seminal vesicles

Questions

1. List contraindications to circumcision
2. What is the differential diagnosis of a penile mass in a child?

Answers

1. List contraindications to circumcision
2. What is the differential diagnosis of a penile mass in a child?

References

• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 4, chap 146