Penile conditions: Pathology review

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Case Studies0:00–0:50

Jacob is a 32 year old male who comes to the emergency department because of a painful, sustained erection, which has lasted five hours now.
Upon further questioning, Jacob tells you that he takes antidepressant medications. You immediately order a penile arterial blood gas analysis, which reveals decreased concentration of oxygen, increased concentration of carbon dioxide, and decreased arterial pH.
Next you see Tafari, a 55 year old male of African descent. Tafari is worried because he developed a lesion on the glans penis about six months ago, and it won’t go away.
Upon physical examination, you notice that the lesion looks bright red and has well-defined borders. Finally, you decide to perform an excisional biopsy to remove and analyze the lesion.Okay, based on the initial presentation, both Jacob and Tafari seem to have some form of penile condition.

Pathology0:50–1:53

Now, the penis is made of three long cylindrical bodies: the corpus spongiosum that surrounds the penile urethra, and the two corpora cavernosa that are made of erectile tissue.
The corpora cavernosa are wrapped in a fibrous coat called the tunica albuginea, and each corpus cavernosum is made up of blood-filled spaces called the cavernosal spaces.
These spaces are lined with endothelial cells surrounded by smooth muscle. Running down the center of each corpus cavernosum is a large artery called the deep artery, which gives off smaller arteries that supply the cavernosal spaces.
Next, blood gets drained from these spaces by small emissary veins, which drain into the deep dorsal vein. This vein then carries the blood back into the systemic circulation.
Now, for your exams, some high yield penile conditions you must absolutely remember include Peyronie disease, priapism, and squamous cell carcinoma of the penis.Let’s start with Peyronie disease, which refers to an abnormal curvature of the penis.

Peyronie disease1:53–2:59

For your exams, make sure you don’t confuse this disease with a penile fracture, where penile injury may result in rupture of the corpora cavernosa, leading to an abnormal penile curvature.
In contrast, the cause of Peyronie disease is not fully understood, however, it’s thought to be associated with repeated microtrauma during sexual intercourse.
This is followed by local inflammation and collagen deposition creating a fibrous plaque in the tunica albuginea. The most common symptoms of Peyronie disease include a visibly curved penis that may progress or stabilize over time.
This is often accompanied by penile pain and erectile dysfunction, where an individual is unable to develop or maintain an erection.
Keep in mind that this may increase the risk for psychiatric conditions, like anxiety or depression. Diagnosis of Peyronie disease is usually clinical, and treatment involves injections of collagenase, which helps degrade collagen within the lesion, once the curvature gets stabilized.
In more severe cases, surgical repair might be recommended.Next is priapism, which refers to a prolonged penile erection that occurs in the absence of sexual arousal, often lasts for more than four hours, and is not relieved by ejaculation.

Priapism2:59–5:53

For your exams, remember that there are two main types of priapism: ischemic or low-flow priapism and nonischemic or high-flow priapism.
What helps you set these two apart clinically is that in the case of ischemic priapism, the erection is painful and rigid, in contrast to nonischemic priapism, where the erection is typically painless and not fully rigid.Now, the most common and high yield type is ischemic or low-flow priapism, which occurs when there’s insufficient venous drainage from the corpora cavernosa.
This means that blood can’t leave through the veins, so it backs up, slowing down the blood flow through the arterial side as well!
As a result, less oxygenated blood gets to the penis, which leads to ischemia. Now, insufficient venous drainage is often due to blockage of draining venules.
An important cause for your exams is sickle cell disease, where sickled red blood cells get stuck in the walls of those venules, clogging up blood flow.
So, if a test question mentions a child with priapism, think of sickle cell disease! On the other hand, the most common cause of priapism among adults are medications, including antidepressants like trazodone, and phosphodiesterase-5 or PDE-5 inhibitors like sildenafil, which are used to treat erectile dysfunction.
Now, there’s also nonischemic or high-flow priapism, which is less common. Here, the problem is excessive cavernous arterial inflow from a fistula that connects the deep artery and corpus cavernosum.
Usually, this occurs as a result of genital trauma or penetrating injury. Diagnosis of priapism is mainly clinical, but penile arterial blood gas analysis can be done to differentiate between ischemic and nonischemic priapism.
So, in the case of ischemic priapism, there will be hypoxemia or decreased concentration of arterial oxygen, hypercapnia or increased concentration of arterial carbon dioxide, and acidosis or decreased arterial pH.
On the other hand, in nonischemic priapism, arterial oxygen, carbon dioxide, and pH will all be normal. And that’s a high yield fact!
For treatment, remember that ischemic priapism is a medical emergency and requires immediate injection of phenylephrine in the corpus cavernosum.
This is an alpha adrenergic agonist that causes contraction of the cavernosal smooth muscle, allowing for reentry of oxygenated blood through the penis.
In addition, cavernosal aspiration of blood can be performed to further promote venous outflow. Finally, if none of these works out, surgical decompression is recommended.
On the other hand, nonischemic priapism typically resolves spontaneously without treatment.Last but not least is squamous cell carcinoma of the penis.

Squamous cell carcinoma of the penis5:53–8:06

This is a rare type of cancer that’s most commonly seen in people of African, Asian, or South American descent. For your exams, it’s important to know that the main risk factors include infection by the human papillomavirus, or HPV, as well as phimosis, which is when the foreskin can’t be pulled back from the glans or head of the penis.
On the flip side, keep in mind that a protective factor is circumcision, probably because it helps prevent phimosis. Now, what’s extremely high yield is that squamous cell carcinoma of the penis can develop from certain precursor or in situ lesions, meaning that they involve the full thickness of the epidermis but without infiltration into the dermis.
In situ lesions that have clear malignant potential include Bowen disease and erythroplasia of Queyrat. Now, Bowen disease usually appears as red, shiny patches or plaques on the shaft of the penis.
On the other hand, erythroplasia of Queyrat appears as erythroplakia, or well-demarcated erythematous plaques that may look very similar to Bowen disease, but they most commonly appear on the glans penis.
So, in a test question, the main clue to help you distinguish Bowen disease from erythroplasia of Queyrat is their location.
Now, another high yield in situ lesion is Bowenoid papulosis, however, its malignant potential or ability to develop into squamous cell carcinoma is unclear.
Bowenoid papulosis typically appears as multiple, warty-like, red or brown papules that may involve the penile shaft, glans, or foreskin.
Now, in situ lesions may evolve into squamous cell carcinoma of the penis, which breaks through the basement membrane of the epidermis, infiltrates into the dermis, and may even reach the hypodermis.
Squamous cell carcinoma can appear as a firm, red, and well circumscribed elevation of the skin or mucosa. As the lesion grows, the center may become necrotic and can eventually turn into an ulcer.
In addition, some lesions may be painful or pruritic. Diagnosis of both in situ lesions and squamous cell carcinoma is usually clinical, followed by an excisional skin biopsy that’s performed both to confirm the diagnosis and for treatment.

Review8:06–9:13

All right, as a quick recap …Peyronie refers to an abnormal penile curvature, often accompanied by pain and erectile dysfunction, that’s thought to be due to repeated microtrauma during sexual intercourse, leading to the formation of a fibrous plaque in the tunica albuginea.
Next, priapism is classified into ischemic or low-flow priapism, and nonischemic or high-flow priapism; ischemic priapism is more common, and refers to a prolonged, painful, rigid erection that results from inadequate venous drainage, which can occur due to sickle cell disease or medications like trazodone or sildenafil; on the other hand, nonischemic priapism is less common, presents as a prolonged, but painless and not fully rigid erection, and is caused by excessive cavernous arterial inflow.
Finally, squamous cell carcinoma of the penis is most common in people of African, Asian, or South American descent; a protective factor is circumcision, while risk factors include HPV and phimosis, and precursor in situ lesions include Bowen disease, erythroplasia of Queyrat, and Bowenoid papulosis.
Okay, back to our cases! Jacob is a 32 year old male that came in because of a five-hour long erection, which points to priapism.

Summary9:13–10:12

A big clue is the fact that Jacob uses antidepressant medications, which is the most common cause of priapism among adults in the US.
Now, since the erection is painful, it’s probably ischemic or low-flow priapism. This is confirmed by the penile arterial blood gas analysis, which reveals hypoxemia, hypercapnia, and acidosis.
On the other hand, Tafari is a 55 year old black male who presents with a non-healing lesion on the glans penis. This location should make you think of erythroplasia of Queyrat or Bowenoid papulosis.
However, physical examination reveals that Tafari’s lesion is a well-demarcated erythematous plaque, which is characteristic of erythroplasia of Queyrat, and diagnosis was confirmed with an excisional biopsy to prevent its progression into squamous cell carcinoma of the penis, which remember is more common in people of African descent.
Penile conditions: Video, Causes, and Symptoms | Osmosis