Overview
Anatomy
The penis is made up of:
- Glans:
- Also known as the head of the penis
- Covered by the prepuce, also known as foreskin
- Penile shaft:
- Made up of 2 columns of erectile tissue known as:
- Corpus cavernosa
- Corpus spongiosum
- These regions are covered by a membrane: tunica albuginea
- Made up of 2 columns of erectile tissue known as:
- Urethra:
- Runs from the bladder through the center of the penis
- Terminates with an opening at the tip of the glans, called the urethral meatus
Classification
Penile conditions can be classified on the basis of the affected region of the penis:
- Glans and prepuce:
- Balanitis
- Phimosis
- Paraphimosis
- Penile shaft:
- Peyronie disease
- Priapism
- Urethra:
- Epispadias
- Hypospadias
Epispadias and Hypospadias
Epispadias
- Definition: abnormal opening of the urethra on the dorsal surface of the penis
- Epidemiology:
- Very rare
- Reported incidence: < 1 in 100,000 male newborns
- Etiology:
- Defective migration of the genital tubercle → incomplete urethral tubularization
- Associated with abnormal abdominal wall defects, such as exstrophy of the bladder
- Clinical presentation:
- Meatal opening on the dorsum of the penis
- Ventrally hooded prepuce
- Associated with curvature of the penis (chordee)
- Diagnosis: often made at the time of newborn genital examination
- Management: surgical closure and reconstruction
- Complications:
- ↑ Frequency of urinary tract infections (UTIs)
- Urinary incontinence
- Urinary reflux
- Infertility
Male baby with epispadias
Image: “Male baby with epispadias” by Department of Pediatric Urology, University Medical Center Regensburg, Germany. License: CC BY 2.0Hypospadias
- Definition: abnormal opening of the urethra on the ventral surface of the penis
- Epidemiology:
- Most common congenital penile defect
- Occurs in approximately 1 in 250 male newborns in the United States
- Etiology:
- Due to failure of urethral folds to close
- Cause is multifactorial
- May be associated with the following factors:
- Environmental
- Genetic
- Endocrine
- Clinical presentation:
- Meatal opening on the ventral surface of the penis
- Deficient foreskin on the ventral surface → incomplete foreskin closure around the glans
- Associated with chordee
- Diagnosis: often made at the time of newborn genital examination
- Management:
- Surgical correction
- Not warranted for those with mild defects
- Complications:
- ↑ Risk of UTIs
- Urinary incontinence
- Urinary obstruction
- Infertility
The difference between hypospadias and epispadias: Hypospadias results in an abnormal urethral opening on the ventral surface of the penis, whereas epispadias results from an abnormal opening on the dorsal surface.
Image by Lecturio.
Glanular hypospadias
Image: “Glanular hypospadias is detected with the retraction of the foreskin” by Yesildag E et al. License: CC BY 3.0
Abnormal opening on the ventral surface of the penis consistent with hypospadias
Image: “Depiction of a human penis with hypospadias” by Buddy. License: Public Domain
Phimosis and Paraphimosis
Phimosis
- Definition: inability to retract the prepuce over the glans
- Epidemiology: 1 of the most common penile abnormalities
- Etiology:
- Physiologic:
- Occurs in almost all male newborns
- Due to normal development of congenital adhesions between the prepuce and glans
- Pathologic:
- Nonretractable prepuce secondary to scarring
- Usually a result of infection and inflammation
- Physiologic:
- Clinical presentation:
- Nonretractable prepuce
- Physiologic: “ballooning” of the prepuce with urination
- Pathologic:
- Contracted, white, fibrous ring → scarring
- Pain
- Skin irritation
- Hematuria
- Diagnosis: physical examination
- Management:
- Physiologic phimosis is self-limiting.
- Good hygiene
- Gentle dilation and stretching
- Topical corticosteroid cream
- Circumcision
- Complications:
- Paraphimosis
- Balanitis
- ↑ Risk of penile cancer
An erect penis with phimosis
Image: “Example of an erect penis with Phimosis. The foreskin will not retract.” by Andrew1985. License: Public DomainParaphimosis
- Definition: condition in which the prepuce of an uncircumcised penis gets trapped behind the glans and cannot be reduced:
- Can lead to strangulation and infarction of the glans
- Considered a urologic emergency
- Etiology: several potential predisposing factors:
- Phimosis
- Trauma
- Sexual activity
- Procedures (usually due to not replacing the prepuce over the glans after the procedure):
- Cystoscopy
- Catheterization
- Clinical presentation:
- Swelling
- Pain and tenderness
- Constricting band of tissue proximal to the glans
- Retracted prepuce does not easily reduce manually
- If not corrected: ischemia or necrosis → blue or black discoloration
- Diagnosis: physical examination
- Management:
- Pain control
- Manual reduction
- Surgical intervention:
- Dorsal slit reduction (incision of the constricting band)
- Emergent circumcision
- Complications: necrosis of the glans
Paraphimosis complicated by glans gangrene:
This condition is caused by impairment of lymphatic and venous blood flow, leading to swelling and compromise of arterial blood flow.
Balanitis
Definition and epidemiology
- Balanitis is inflammation of the glans penis.
- Affects approximately 3% of uncircumcised males globally
Etiology
- Predisposing factors:
- Inadequate cleaning of the penis and foreskin
- Phimosis
- Exposure to irritants:
- Soaps
- Lubricants
- Latex
- Dermatologic conditions:
- Allergic reaction
- Eczema
- Psoriasis
- Lichen planus
- Trauma
- Chronic medical conditions, such as:
- Diabetes
- Obesity
- Congestive heart failure or other edematous conditions
- Common infectious causes:
- Candida
- Bacteria
- Neisseria gonorrhoeae
- Group B streptococci
- Chlamydia
- Anaerobes
- Treponema pallidum
- Trichomonas
- Herpes simplex
- Scabies
Clinical presentation
- Erythema
- Edema of the glans
- Pain and tenderness
- Pruritus
- Tight foreskin
- Purulent exudate
- Ulcerated lesions of the glans and prepuce
- Urinary obstruction
- Lymphadenopathy
Erythema and edema of the glans penis consistent with balanitis
Image: “Balanitis caused by smegma” by MFN24. License: CC0 1.0Diagnosis
- Physical examination
- Further workup is determined based on the history, but may include:
- Bacterial cultures
- Herpes simplex virus testing
- Potassium hydroxide preparation → assess for Candida
- Gonorrhea and chlamydia testing
Management
- Good hygiene, with adequate cleaning of the penis and foreskin
- Avoid irritants
- Treatment of underlying infection, if present
- Management of chronic, predisposing conditions
Complications
- Phimosis
- Paraphimosis
- ↑ Risk of penile cancer
- Urethral stricture
Peyronie Disease
Definition
Peyronie disease is a penile deformity caused by fibrosis/scarring of the tunica albuginea.
Epidemiology
- Prevalence: approximately 5% of men (likely underreported)
- Mean age: approximately 68 years
Etiology
- Fibrous plaques may occur because of:
- Trauma
- Tissue ischemia
- Risk factors:
- Urologic procedures:
- Catheterization
- Cystoscopy
- Transurethral resection of the prostate
- Connective tissue disorders
- Genetics
- Hypogonadism
- Diabetes
- Tobacco use
- Alcohol use
- Older age
- Urologic procedures:
Clinical presentation
- More often evident with an erection
- Deviation of the penis to the affected side
- Pain
- Palpable nodules or plaques
Abnormal curvature of the penis secondary to Peyronie disease
Image: “Penile deformity secondary to Peyronie’s disease” by Tran VQ et al. License: CC BY 3.0Diagnosis
The diagnosis is clinical.
Management
- Observation (for those with mild, stable disease)
- Medical therapy:
- Pentoxifylline → prevents collagen deposition and fibrosis
- Intralesional injections:
- Collagenase
- Verapamil → ↑ collagenase activity, ↓ collagen production
- Surgical repair for severe cases
Complications
- Erectile dysfunction
- Psychologic effects:
- Anxiety
- Low self-esteem
Priapism
Definition
Priapism is an abnormal, persistent erection (usually > 4 hours) that is not associated with sexual stimulation.
Epidemiology
- Incidence: 0.73 case per 100,000 men per year
- Ischemic priapism is more common (approximately ⅔ of cases are associated with erectile dysfunction treatment).
- Bimodal age distribution:
- 5–10 years
- 20–50 years
Etiology and pathophysiology
- Ischemic:
- Caused by failure of venous outflow, which can be due to:
- Excessive neurotransmitters
- Blocked venules → prevent venous drainage
- Prolonged smooth muscle relaxation
- Can lead to compartment syndrome → tissue damage
- Causes:
- Drugs (e.g., sildenafil, amphetamines, hydralazine, prazosin)
- Sickle cell disease
- Leukemia
- Vasculitis
- Hypercoagulable state
- Caused by failure of venous outflow, which can be due to:
- Nonischemic:
- Arterial fistula formation → abnormal arterial flow into the corpora cavernosa
- No venous outflow obstruction
- Usually from a direct injury
Clinical presentation
- Ischemic:
- Painful erection
- Rigid
- If not treated → necrosis
- Nonischemic:
- No pain with erection
- Less rigid
- Not associated with necrosis
Diagnosis
The diagnosis is suspected on the basis of the history and physical exam. The following can help differentiate ischemic from nonischemic priapism:
- Cavernosal blood gas:
- Ischemic:
- Blood sample will appear black
- Hypoxia
- Hypercarbia
- Acidosis
- Nonischemic:
- Blood sample will be red
- Normal oxygen
- Normal carbon dioxide
- Normal pH
- Ischemic:
- Doppler ultrasound:
- Ischemic: minimal or absent blood flow in the cavernosal arteries
- Nonischemic: normal or high arterial blood flow
Management
- Ischemic:
- Urologic consultation
- Cavernosal aspiration
- Intracavernosal phenylephrine injection → induce smooth muscle contraction → ↑ venous outflow
- Surgery
- Nonischemic:
- May resolve spontaneously
- Arteriography with embolization
Complications
Complications of ischemic priapism include:
- Erectile dysfunction
- Penile necrosis
References
- Fahmy, M. (2018). Congenital Anomalies of the Penis. Springer.
- Baskin, L.S. (2020). Hypospadias: pathogenesis, diagnosis, and evaluation. UpToDate. Retrieved August 10, 2021, from https://www.uptodate.com/contents/hypospadias-pathogenesis-diagnosis-and-evaluation
- Baskin, L.S. (2020). Hypospadias: management and outcome. UpToDate. Retrieved August 10, 2021, from https://www.uptodate.com/contents/hypospadias-management-and-outcome
- Wilcox, D. (2021). Care of the uncircumcised penis in infants and children. UpToDate. Retrieved August 13, 2021, from https://www.uptodate.com/contents/care-of-the-uncircumcised-penis-in-infants-and-children
- Tews, M. (2020). Paraphimosis: clinical manifestations, diagnosis and treatment. UpToDate. Retrieved August 13, 2021, from https://www.uptodate.com/contents/paraphimosis-clinical-manifestations-diagnosis-and-treatment
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- Rabinowitz, R., Cubillos, J. (2020). Penile and urethral anomalies. MSD Manual Professional Version. Retrieved August 19, 2021, from https://www.msdmanuals.com/professional/pediatrics/congenital-renal-and-genitourinary-anomalies/penile-and-urethral-anomalies
- Anand, S., Lotfollahzadaeh, S. (2021). Epispadias. StatPearls. Retrieved August 19, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK563180/
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