Scrotum,Testis,andEpididymis
Ureter,Bladder,andUrethra
Among the most common malformations of the penis are those in which the distal urethral orifice is abnormally located. In hypospadias, the abnormal urethral opening is found on the ventral aspect of the penis anywhere along the shaft. This anomalous orifice is sometimes constricted, resulting in urinary tract obstruction and an increased risk for urinary tract infections. Hypospadias occurs in 1 in 300 live male births and may be associated with other congenital anomalies, such as inguinal hernia and undescended testis. In epispadias, which is less common, the abnormal urethral orifice is on the dorsal aspect of the penis.
Balanitis and balanoposthitis refer to local inflammation of the glans penis and of the overlying prepuce, respectively. Among the more common agents are Candida albicans, anaerobic bacteria, Gardnerella, and pyogenic bacteria. Most cases occur as a consequence of poor hygiene in uncircumcised males, leading to the accumulation of desquamated epithelial cells, sweat, and debris, termed smegma, which acts as a local irritant. Phimosis is a condition in which the prepuce cannot be retracted easily over the glans penis. Phimosis may be a congenital anomaly, but most cases stem from scarring of the prepuce caused by balanoposthitis.
More than 95% of penile neoplasms arise on squamous epithelium. In the United States, squamous cell carcinomas of the penis are relatively uncommon, accounting for about 0.4% of all cancers in males. In developing countries, however, penile carcinoma occurs at much higher rates. Most cases occur in uncircumcised patients older than 40 years of age. Several factors have been implicated in the pathogenesis of penile squamous cell carcinoma, including poor hygiene (with resultant exposure to potential carcinogens in smegma), smoking, and infection with human papillomavirus (HPV), particularly types 16 and 18.
Squamous cell carcinoma in situ of the penis (Bowen disease) occurs in older uncircumcised males and appears grossly as a solitary plaque on the shaft of the penis. Histologic examination reveals dysplastic cells throughout the epidermis with no invasion of the underlying stroma (
Fig.
18.1 ). It gives rise to invasive squamous cell carcinoma in approximately 10% of patients.
Invasive squamous cell carcinoma of the penis appears as a gray, crusted, papular lesion, most commonly on the glans penis or prepuce. In many cases, infiltration of the underlying connective tissue produces an indurated, ulcerated lesion with irregular margins (
Fig. 18.2 ). Histologically, the tumor is most often a typical keratinizing squamous cell carcinoma. The prognosis is related to the stage of the tumor. With localized lesions, the 5-year survival rate is 66%, whereas metastasis to inguinal lymph nodes carries a grim 27% 5-year survival rate. Verrucous carcinoma is a non-HPV–related variant of squamous cell carcinoma characterized by papillary architecture, virtually no cytologic atypia, and rounded, pushing deep margins. Verrucous carcinomas are locally invasive but do not metastasize.
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Fig. 18.1 Carcinomainsitu(Bowendisease)ofthepenis.Theepitheliumabovetheintactbasementmembraneshowsdelayedmaturationanddisor-ganization(left). Highermagnification(right) showsseveralmitoticfigures,someabovethebasallayer,andnuclearpleomorphism.