Overview of the Penis

The Penis

Basic Anatomy

o        Ventrally, the penile urethra is surrounded by corpus spongiosum

o        Dorsally, are the corpora cavernosa and the glans penis.

o        The whole penis is covered by skin, stratified squamos epithelium.

Basic histology

o        We can see stratified squamous epithelium on the outer surface, surrounded by a highly vascular connective tissue stroma. There is an intact basement membrane. Note the different layers of the epidermis. This is a section of the glans penis.

Pathology

o        Penile pathologies involve congenital anomalies, inflammations (gonorrhea, syphilis, etc), and tumors. We will only talk about the tumors, leaving an understanding of interesting conditions such as BALANITIS for our own personal study.

Tumors

• Condyloma Accuminatum aka Genital Warts
  • While not tumors per se (sp?), infection by HPV (which causes genital warts, but may also be asymptomatic) has potential to cause cancer.
  • Genital warts are transmitted basically by sexual contact, so that viral particles from one person can get onto another person.
  • External genital warts are caused by HPV 6, 11, 42, and 44
  • In women, cervical dysplasia and carcinoma are associated with HPV 16, 18, 31, 33, 35.
  • Diagnosis: 5% acetic acid may color sublinical, flat condylomas whitish.
  • Tx of HPV infection: remove exophytic warts and to decrease signs and symptoms the patient may have from the virus (because it is not possible to get rid of the virus itself)
    • How? Excision, laser ablation, cryotherapy, podophyllin, 5 fluorouracil or thiotepa
    • Educate patient that they are infective to sexual partners and to use condoms
    • HPV vaccine is undergoing clinical trials
  • HPV infection is much more problematic in AIDS pts. Why? Because the symptoms are worse, and the treatment doesn’t work as well.

  

  • Histology
    • Genital warts can be sessile or pedunculated, single or multiple on the shaft of the penis. Histologically, we see fingerlike projections of thickened stratum corneum and lots of keratin formation.

    
     

    • The cells that are infected are known as koilocytes. They have a large, irregular nucleus, which is raisinoid. The cytoplasm is condensed and looks like a halo around the raisin. These cells can be found on the surface of the wart
• Carcinoma in situ
  • When HPV 16 or 18 is causing the condyloma, the cells can undergo dysplasia and neoplasia causing a not yet malignant  carcinoma in-situ
  • There are three such occurrences (i.e. examples of carcinoma in situ):
    • Bowen disease à younger men, white plaques, may ulcerate and become red due to hemorrhage

    
     

    • Erythroplasia of Queyrat (above) à velvety red plaque on glans
    • Bowenoid papulosis à younger men, blackish purple papules on shaft and scrotum.
    • All three have similar histological findings, but clinical differences. Bowenoid papulosis does not have malignant potential, while the others do.

    
     

    • Histologically, on the bottom left you can see epithelium which is abnormal. They have lost the histological organization characteristic of stratified squamos epithelium. They have a high nucleus to cytoplasm ratio. They are still bounded by an intact basement membrane (i.e. they are carcinoma in situ). A closer look would show abnormal mitotic figures.

• Squamous cell Carcinoma of the Penis

  • Penile carcinoma is less than 1% of all male cancers and is very rare in circumcised males. However, data are not enough to recommend routine neonatal circumcision. There is data that good hygiene is a very important factor. In the uncircumcised patient, good hygeiene is rendered even more important.
  • It (invasive and in situ penile carcinoma) is commonly associated with HPV 16 and 18 (also 31 and 33)  as well as smoking.
  • It usually arises in those age 40 – 70.
  • Squamos cell carcinomas usually follow a very indolent course.
  • Grossly, they can present like cauliflower-like lesions (see below) on the glans, or can also resemble plaques     

  
   

  • Can be painless or painful, depending on ulceration or infection.
  • Can be well differentiated or not well differentiated

• Verrucous Carcinoma

  
   

  • Although this is a carcinoma, it is NOT malignant. I.e. it does not ever breach the basement membrane but does invade local deep tissues and exert pressure effects.
  • Associated with HPV 6 and 11.
  • Grossly (see bottom left), they look like warts. Histologically they resemble the koilocytes of warts, but they are cancerous!
  • Histologically, you will also see papillary fronts of thickened cells that are locally invasive, but the basement membrane stays intact so that it doesn’t metastasize. It remains in-situ.
• Penile carcinoma treatment
  • Treatment is absolutely necessary. Without treatment, a patient with penile cancer will die within 2 years.
  • Types of treatment.
    • Partial or total penectomy (ouch!)

    

    • Radiation therapy or Moh’s microscopic surgery where appropriate
    • Patients with high grade (T2 or greater) disease require inguinal lymphadenectomy, a procedure with many complications
    • Radiation therapy and chemotherapy have limited effectiveness but can be used in conjunction with surgery to reduce in size and remove bulky inguinal nodes
• Staging (see top right of this page)à (I couldn’t understand Guruli at all, just so you know)
  • T4 = lymph node involvement
  • T2 = infiltration into erectile tissues
  • T1 = localized to periphery

Back to the Reproductive System Index