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.
- 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.
- 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
Epidemiology
In countries with high circumcision rates the incidence of squamous cell
carcinoma of the penis is very low and correspondingly more common in countries
where the practice is not routine. The tumor is rare in men circumcised at
birth and occurs with higher frequency in uncircumcised individuals with congenital
phimosis. No single etiologic agent has been identified but the association
with phimosis and the protection afforded by circumcision is thought to be
due an unidentified carcinogen in smegma, which accumulates under the prepuce
in uncircumcised males. HPV 16, and to a lesser extent 18, has been suggested
as causal factors.
Question: In what other genital cancers do HPV subtypes play a role.
Early lesions present as an ulcer, nodule or warty growth on the glans or
inner surface of the prepuce. More advanced tumors are usually large, ulcerated
and fungating. The presence of a prepuce may obscure the tumor until it is well
advanced. Most patients are reluctant to seek early medical attention, and tumors
are often advanced at the time of presentation with extensive destruction of
the organ.
Squamous cell carcinoma of the penis. Fungating lesion with complete destruction
of the glans.
The tumor may invade deeply and extend along the shaft, destroying portions
of it.
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.
Question: What lymph node groups do carcinomas of the penis spread
to?
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