Sphincter and Lower Rectum
The estimation of sphincter tone is of importance. Laxity of the muscle suggests similar changes in the urinary sphincter and detrusor and the possibility of neurogenic disease; the same is true for a spastic anal sphincter. In addition to the digital prostatic examination, the examiner should palpate the entire lower rectum to rule out stenosis, internal hemorrhoids, cryptitis, rectal fistulae, mucosal polyps, and rectal cancer. Testing perianal sensation is mandatory.
A specimen of urine for routine analysis should be collected before the rectal examination. This is of importance, since prostatic massage or even palpation at times forces prostatic secretion into the posterior urethra. If this secretion contains pus, a specimen of voided urine after the rectal examination will be contaminated.
The average prostate is about 4 cm in both length and width. As the gland enlarges, the lateral sulci become relatively deeper and the median furrow becomes obliterated. The clinical importance of prostatic hyperplasia is measured by the severity of symptoms and the amount of residual urine rather than by the size of the gland on palpation. The prostate may be of normal size and consistency on examination in a patient with acute urinary retention or severe obstructive urinary complaints.
Normally, the consistency of the gland is similar to that of the contracted thenar eminence of the thumb (with the thumb completely opposed to the little finger) and is rather rubbery. It may be mushy if congested (due to lack of intercourse or chronic infection with impaired drainage), indurated (due to chronic infection with or without calculi), or stony hard (due to advanced carcinoma).
The difficulty lies in differentiating firm areas in the prostate: fibrosis from nonspecific infection, granulomatous prostatitis, nodularity from tuberculosis, or firm areas due to prostatic calculi or early cancer. Generally, nodules caused by infection are raised above the surface of the gland. At their edges, the induration gradually fades to the normal softness of surrounding tissue. Conversely, the suspicious lesion in cases of prostate cancer is usually not raised; rather, it is hard and has a sharp edge (ie, there is an abrupt change in consistency on the same plane). It tends to arise in the lateral sulcus (Figure 4–2).
Differential diagnosis of prostatic nodules. A: Inflammatory area is raised above the surface of the gland; induration decreases gradually at its periphery. B: Cancerous nodules is not raised; there is an abrupt change in consistency at its edges.
Even the most experienced clinician can have trouble differentiating cancer from other conditions. The serum prostate-specific antigen (PSA) level can be helpful if elevated and is currently the most common method of diagnosing prostate cancer (clinical stage T1c). Transrectal ultrasound-guided biopsy of the prostate can be diagnostic. Recent evidence suggests that rectal examination after radical prostatectomy is unnecessary when PSA is undetectable, since no case of locally recurrent cancer was identified in the absence of an elevated PSA.
The mobility of the gland varies. Occasionally, it has great mobility while at other times, very little. With advanced carcinoma, it is fixed because of local extension through the capsule. In adults, the prostate should be routinely massaged and its secretion examined microscopically. However, prostatic massage should be avoided in the presence of an acute urethral discharge, acute prostatitis, or acute prostatocystitis; in men near the stage of complete urinary retention (because it may precipitate complete retention); or in men suffering from obvious cancer of the gland.
Massage and Prostatic Smear
Copious amounts of secretion may be obtained from some prostate glands and little or none from others. The amount obtained depends to some extent on the vigor with which the massage is carried out. If no secretion is obtained, the patient should be asked to void even a few drops of urine, as these will contain adequate secretion for examination. Microscopic examination of the secretion is done under low-power magnification. Normal secretion contains numerous lecithin bodies, which are refractile like red blood cells but much smaller. Only an occasional white cell is present. A few epithelial cells and, rarely, corpora amylacea are seen. Sperm may be present, but its absence is of no significance.
The presence of large numbers or clumps of leukocytes suggests prostatitis. Stained smears are usually impractical because it is difficult to fix the material on the slide; even when fixation and staining are successful, pyogenic bacteria are usually not found. Acid-fast organisms can often be found by appropriate staining methods.
On occasion, it may be necessary to obtain cultures of prostatic secretion in order to demonstrate nonspecific organisms, tubercle bacilli, gonococci, or chlamydiae. After thorough cleansing of the glans and emptying of the bladder to mechanically cleanse the urethra, the prostate is massaged. Drops of secretion are collected in a sterile tube of appropriate culture medium.
Palpation of the seminal vesicles should be attempted. The vesicles are situated under the base of the bladder and diverge from below upward (Figure 1–8). Normal seminal vesicles are usually impalpable, but may feel cystic when overdistended. In the presence of chronic infection (particularly tuberculosis or schistosomiasis) or in association with advanced carcinoma of the prostate, they may be indurated. Stripping of the seminal vesicles should be done in association with prostatic massage, for the vesicles are usually infected when prostatitis is present. Primary tumors of the vesicles are very rare. A cystic mass may rarely be felt over the prostate or just above it. This probably represents a cyst of the Müllerian duct or the utricle; the latter is occasionally associated with severe hypospadias.
It should be remembered that generalized lymphadenopathy usually occurs early in human immunodeficiency syndrome (see Chapter 15).
Inguinal and Subinguinal Lymph Nodes
With inflammatory lesions of the skin of the penis and scrotum or vulva, the inguinal and subinguinal lymph nodes may be involved. Such diseases include chancroid, syphilitic chancre, lymphogranuloma venereum, and on occasion, gonorrhea.
Malignant tumors (squamous cell carcinoma) involving the penis, glans, scrotal skin, or distal urethra in women metastasize to the inguinal and subinguinal nodes. Testicular tumors do not spread to these nodes unless they have invaded the scrotal skin or the patient has previously undergone orchidopexy.
Tumors of the testis and prostate may involve the left supraclavicular nodes (Virchow's or Troisier's node). Tumors of the bladder and prostate typically metastasize to the internal iliac, external iliac, and preaortic nodes, although rarely are they so large as to be palpable. Upper abdominal masses near the midline in a young man should suggest metastases from cancer of the testis; the primary growth may be minute and hidden in the substance of what appears to be a normal testicle.