Male Genital System and Lower Urinary Tract Infection (UTI). Wer are going to read about The most common malformations of the penis include those in which the distal urethral orifice is abnormally localized. In hypospadias, the abnormal urethral opening is found on the ventral side of the penis somewhere along the shaft. This abnormal opening is sometimes narrowed, leading to urinary obstruction and an increased risk of urinary tract infections. Hypospadias occurs in 1 in 300 live male births and can be associated with other congenital abnormalities such as inguinal hernia and undescended testicles. In epispadias, which is less common, the abnormal urethral opening is on the dorsal side of the penis.
Balanitis and balanoposthitis refer to local inflammation of the glans penis or the overlying foreskin. The more common pathogens include Candida albicans, anaerobic bacteria, Gardnerella, and pyogenic bacteria. Most cases occur as a result of poor hygiene in uncircumcised men, which leads to the accumulation of flaky epithelial cells, sweat, and debris called smegma, which act as a local irritant. Phimosis is a condition in which the foreskin cannot easily be pulled back over the glans. Phimosis can be a congenital abnormality, but most cases are due to scarring of the foreskin caused by balanoposthitis.
More than 95% of penile neoplasms arise on the squamous epithelium. Squamous cell carcinoma of the penis is relatively rare in the United States, accounting for about 0.4% of all cancers in men. However, penile cancer is much more common in developing countries. Most cases occur in uncircumcised patients over 40 years of age. Several factors have been implicated in the pathogenesis of squamous cell carcinoma of the penis, including poor hygiene (with the resulting 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’s disease) occurs in older uncircumcised men and appears coarse as a single plaque on the penile shaft. The histological examination reveals dysplastic cells throughout the epidermis without invading the underlying stroma (Fig. 18.1).
It leads to invasive squamous cell carcinoma in about 10% of patients. Invasive squamous cell carcinoma of the penis appears as a grey, crusty, papular lesion, most commonly on the glans penis or foreskin. In many cases, infiltration of the underlying connective tissue results in a hardened, ulcerated lesion with irregular margins (Fig. 18.2). Histologically, the tumour is mostly a typical keratinizing squamous cell carcinoma. The prognosis depends on the stage of the tumour. For localized lesions, the 5-year survival rate is 66%, while metastases in inguinal lymph nodes have a dismal 5-year survival rate of 27%. Verrucous carcinoma is a non-HPV-related variant of squamous cell carcinoma.
Male Genital System and Lower Urinary Tract Infection (UTI)
Several inflammatory processes can affect the skin of the scrotum, including local fungal infections and systemic dermatoses such as psoriasis. New growth of the scrotum is unusual. Squamous cell carcinoma, the most common of them, is of historical interest as it is the first human malignant disease to be associated with environmental exposure and stems from Sir Percival Pott’s observation of a high incidence of the disease in chimney sweeps. The chimney sweep’s guild’s subsequent ordinance that its members bathe daily remains one of the most successful public health measures for cancer prevention. Several disorders unrelated to the testes and epididymis can show up as scrotal enlargement. Hydrocele, the most common cause of scrotum swelling, is caused by a build-up of serous fluid in the tunica vaginalis. It can be idiopathic or it can occur as a reaction to nearby infections or tumors. The clear liquid in a hydrocele lets light through (transluminescence) and distinguishes it from collections of blood, pus or lymph, all of which are cloudy or opaque. The build-up of blood or lymph in the tunica vaginalis, known as a hematocele or chylocele, can also cause the scrotum to enlarge. In extreme cases of lymphobstruction, caused by filariasis, for example, the scrotum and lower extremities can enlarge to grotesque sizes, a condition known as elephantiasis.
Cryptorchidism and Testicular Atrophy
Cryptorchidism is a failure of testicular descent into the scrotum. Usually the testes rise from the abdominal cavity into the pelvis in the third month of pregnancy and then through the inguinal canals into the scrotum during the last 2 months of intrauterine life. The diagnosis of cryptorchidism is only certain from the age of 1, especially in premature babies, since the testicular descent is not always complete at birth. Cryptorchidism affects 1% of the male population. In the vast majority of cases, the cause is unknown. The condition occurs bilaterally in about 10% of affected patients, a small percentage of whom have chromosomal aberrations and other developmental disorders. Since undescended testicles atrophy, bilateral cryptorchidism leads to sterility. For unclear reasons, even unilateral cryptorchidism can be associated with atrophy of the contralateral descending gonads.
In addition to infertility, failure of testicular descent is associated with a 3 to 5-fold increased risk of testicular cancer. Patients with unilateral cryptorchidism are also at increased risk of developing cancer in the contralateral, normally descended testicle, suggesting that an intrinsic abnormality, rather than simple descent failure, underlies the increased risk of cancer. Surgical placement of undescended testicles in the scrotum (orchiopexy) is recommended from the age of 18 months to reduce the likelihood of testicular atrophy, infertility, and testicular cancer The cryptorchid testicle may be normal in size at the beginning of life, but some degree of atrophy usually becomes apparent by the onset of puberty.
On microscopic examination, tubular atrophy begins to appear around the age of 5 to 6 years and has usually progressed through puberty. Germ cell neoplasia in situ (discussed later) may be present in cryptorchid testes and is a likely precursor to subsequent germ cell tumors. Atrophic changes similar to those in cryptorchid testes can be caused by other injuries, including chronic ischemia, trauma, radiation, and antineoplastic chemotherapy, as well as conditions associated with chronically elevated levels of estrogen (e.g., cirrhosis).
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