disorders of the penis

8/8/2019 Disorders of the Penis

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8i888PENIS

I. Gross Anatomy and Histology

Objectives

After reviewing this section you will be able to:

• list and identify the various parts of the penis

• describe the gross anatomy and histology of the penis

A. Anatomy

The penis and scrotum form the male external genitalia. The penis consists of a shaft (bodyor corpus), with an expanded acorn-like end called the glans, and the root. The glans has a

rounded proximal border called the corona that is attached to the body by the neck (which

forms a sulcus or groove). The shaft has a dorsal (antero-superior) surface and a ventral

(urethral or inferior) surface, which faces the scrotum. The penis contains erectile tissue,

three parallel cylindrical bodies containing spongy connective tissue with vascular sinuses.

Fibrous capsules, the tunica albuginea, surround each of these and fuse to hold them

together. Superficial to the tunica is an outer sheath of connective tissue, the penile fascia.

Two of these bodies, called the corpora cavernosa, are on the dorsal aspect of the organ and

the third, the corpus spongiosum, is on the ventral side and contains the urethra. The corpus

spongiosum is expanded at its distal end to form the glans, which covers the distal ends of the

corpora cavernosa. On the tip of the glans is the slit-like orifice of the urethra, the externalurethral meatus.

A cross section through a portion of the penis showing the penile urethra within the body of

the corpus spongiosum. The corpora cavernosa are seen to the right of the urethra (the twoislands). The erectile tissue contains blood spaces and is surrounded by a band of connective

tissue, part of the tunica albuginea. The skin is to the left.



A cross section through a portion of the penis showing the penile urethra within the body of

the corpus spongiosum. The erectile tissue contains blood spaces and is surrounded by a bandof connective tissue, part of the tunica albuginea.

The shaft is covered by thin, hairless and very mobile skin, which doubles back over itself

over the glans to attach to its neck to form a retractable hood called the prepuce or foreskin.

The skin over the glans is much thinner, semitransparent, firmly bound to the tunica

albuginea and, over the lips of the urethral meatus is continuous with the urethral mucosa.

The skin on the ventral surface has a midline raphe continuous with the scrotal raphe.

The proximal end of the corpus spongiosum is lightly expanded and forms the bulb while the

ends of the two cavernosa diverge to form the crura. The bulb and crura form the root of the

penis.



II. Congenital Anomalies

Objectives:

After completing this section will know:

• the most frequently encountered congenital abnormalities

• the distinguishing features of various abnormalities

• the clinical importance of each abnormality

Congenital malformations of the penis are relatively uncommon. The most frequently

encountered abnormalities involve the formation of the urethral groove and the prepuce.

A. Hypospadias

When the urethra opens abnormally on the ventral (inferior) surface of the penis, the

condition is termed a hypospadias.

B. Epispadias

This term is used to describe the condition in which the abnormal urethral opening is on the

dorsal surface of the penis. It is rare and is almost invariably associated with defects in the

urethral valve, leading to urinary incontinence. Patients with hypospadias do not typically

have this difficulty.

These conditions are important because they are usually associated with recurrent

infections. The abnormal opening may be constricted causing partial urinary

obstruction, which leads to bacterial spread from the blocked penile urethra into the

bladder. Also infertility may result from inability to properly inseminate. Both

conditions are amenable to plastic surgical correction.

C. Phimosis

When the foreskin or prepuce cannot be retracted over the glans because of an abnormally

small orifice, the patient is said to have a phimosis. The condition may also be acquiredthrough inflammatory scarring of the prepuce. It is the most common of the penile

malformation.

D. Paraphimosis

When a phimotic prepuce is forcibly retracted over the glans and cannot be restored,

paraphimosis results. This causes painful swelling of the glans and is a medical emergency

because of the compromised blood flow with the potential for gangrenous necrosis of the

glans. Also urethral constriction causes acute retention of urine.



III. Infectious Diseases

Objectives:

After completing this section you will be able to:

• describe the various types of inflammatory conditions that involve the

penis

• indicate etiologic agents

• describe and identify clinical lesions

A plethora of viral, bacterial, fungal, and protozoan organisms may infect the penis via both

venereal and non-venereal transmission.

A. Balanoposthitis

This is nonspecific penile infection with inflammation of both the glans (balanitis) and the

prepuce. Usually the patient has a phimosis or a large, redundant prepuce that interferes with

cleanliness. The offending organism is frequently a Staphylococcal or Streptococcal species

but may also be caused by Candida albicans. The condition may lead to frank ulceration of

the glans.

B. Condyloma accuminatum

This is a viral infection caused by the human papillomavirus (HPV) type 6 or 11 that

produces a warty growth. It is spread by venereal or by less direct means.

The lesions occur, most often, about the coronal sulcus and inner surface of the

prepuce as single or multiple, sessile or pedunculated, red papillary excrescences of

varying sizes.

Note the warty masses on the glans of the penis.



Multiple large warty growths are present on the ventral aspect of the glans and neck of the

penis.

Histologically, the lesions present as branching, finger-like, papillary connective

tissue stroma covered by thickened, hyperplastic epithelium, which may show

excessive surface keratinization. Koilocytes may be noted in the superficial zone of

the epithelium. Cellular atypia is absent.

C. Condyloma lata (Syphilitic wart)

This occurs in secondary syphilis and develops 2 to 8 weeks after the primary chancre. It is

highly infectious and presents as gray-white to erythematous, painless, broad, moist plaques.

Condyloma lata. White plaques are present on the skin of the shaft and prepuce.



IV. Benign Conditions

Objectives:

After completing this section you will be able to:

• describe the clinical features of Peyronie’s disease and priapism

• state relevant associations and complication

A. Peyronie's Disease (Penile Fibromatosis)

This is a disease of unknown cause characterized by focal, fibrous induration of the shaft of

the penis associated with abnormal curvature and painful erection. It is associated with

Dupuytren's contracture (palmar fibromatosis), which is present in about 25% of cases.

Histologically, dense fibro-collagenous tissue is present in the tunica albuginea or

between the tunica and the penile fascia.

The lesion usually recurs after surgical removal.

B. Priapism

This refers to unwanted, inappropriate (unrelated to sexual activity), persistent, painful

erection. Priapism is distinguished from normal erection by absence of tumescence of the

glans. It may be idiopathic, associated with sickle cell disease, chronic granulocytic leukemia,

spinal cord injury, or secondary to injection of vasodilator agents (e.g. PGE1) into the penis,

drugs (e.g. trazadone), thrombosis of the penile veins or to adrenergic-mediated mechanism

for detumescence. In priapism of sickle cell disease, the corpora cavernosa are usually

engorged and the glans and corpus spongiosum are spared. In a minority however, tricorporal

priapism occurs. Priapism, especially tricorporal, may eventuate in impotence.

V. Premalignant and Malignant Neoplasms

Objectives:

After completing this section you will know:

• the definition of carcinoma-in-situ

• the various types of carcinoma-in-situ of the penis, their locations and malignant

potential

• the most important factors in the development of carcinoma of the penis

• the clinical and histologic features of carcinoma of the penis

• the natural course and prognosis of carcinoma of the penis

Carcinomas of the penis are exclusively of the squamous cell type.

A. Squamous Cell Carcinoma-In-Situ



This is a pre-cancerous lesion in which the epithelium has all the cytological features of

malignancy but is confined to the epithelium without penetration of the basement membrane.

Carcinoma-in-situ of the penis and surrounding genital region is also called erythroplasia of

Queyrat or Bowen's disease. Lesions involving the shaft of the penis are referred to as

Bowen's disease while those affecting the glans and prepuce are called erythroplasia.

Clinically, these lesions present as erythematous plaques. Erythroplasia of Queyrat

occurs almost exclusively in uncircumcised males and, on the average, in men slightly

younger than those with Bowen's disease.

Erythroplasia of Queyrat presenting as an erythematous lesion involving the ventral aspect

and tip of the glans.

Erythroplasia of Queyrat. Erythematous lesions on the glans and neck of the penis.



Bowen’s disease. Erythempatous lesion involving the distal shaft and groins.

The histologic picture of carcinoma-in-situ is that of a thickened epithelium with

complete architectural disorganization, enlarged, hyperchromatic nuclei and atypical

mitotic figures. A chronic inflammatory infiltrate in the subjacent dermis is typically

present.

Bowen’s disease. Thickened squamous epithelium (acanthosis) with irregular elongation of

the papillae (papillomatosis), cytologic atypia and many mitoses, some abnormal.



Bowen’s disease. High power photomicrograph showing complete architectural

disorganization with loss of polarity, nuclear pleomorphism and mitotic figures.

Another condition called Bowenoid papulosis occurs in younger patients on the shaft

of the penis. They are smaller, often multiple and histologically are no different from

Bowen's disease. HPV 16 antigens have been demonstrated in most cases of Bowenoid papulosis.

In spite of the different names, they are variants of the same disease and some prefer

to call all three lesions intraepithelial neoplasia. If left untreated, some carcinoma-in-

situ of the penis will regress and others will progress to invade underlying stroma.

The frequency with which progression to full-fledged squamous cell carcinomas

occurs is uncertain. Bowenoid papulosis has not been clearly documented to progress.

B. Verrucous carcinoma (Giant condyloma of Buschke - Löwenstein)

This is an extensive, exophytic, warty or cauliflower-like tumor of the penis that involves

and, often, destroys the glans and the prepuce.

The lesion shows the histologic features of condyloma accuminatum. However, in

addition to the upward growth of the epithelium, there is downward proliferation of

the epithelium with the papillae forming broad, compressive fronts into the underlying

tissue, which is destroyed. Focal cytologic atypia may be seen in the epithelium.

Although the histologic picture appears benign, the lesion behaves as a low-grade

squamous cell carcinoma with true invasion through the basement membrane

occurring late in its evolution. Surgical removal of the tumor is usually curative.



Squamous cell carcinoma. Serial blocks of the penile shaft showing extensive involvement.

Histologically, the tumors are usually well to moderately differentiated squamous cell

carcinomas with focal keratinization and rarely poorly differentiated. Invasion of the

dermis is in the form of irregular cords or small clumps.

Because of late presentation approximately 20% of patients will have lymph node

involvement at presentation. The prognosis of disease limited to the penis is quite

good with 90 to 95% 5-year survival. With lymph node metastases 5-year survival is

reduced to less than 50%. Systemic spread is rare.

disorders of the penis

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