Reproductive System

Chapter 11


Reproductive System




Objectives


After reading this chapter, the reader will be able to:


1 Define and describe all bold-faced terms in this chapter


2 Describe the physiology of the reproductive system


3 Identify anatomic structures on both diagrams and radiographs of the reproductive system


4 Differentiate various pathologic conditions affecting the reproductive system and their radiographic manifestations


5 Initiate alterations that must be made in routine exposure techniques to obtain optimal-quality radiographs



Key terms




Infectious diseases of both genders



Syphilis


Syphilis is a chronic, sexually transmitted systemic infection caused by the spirochete Treponema pallidum. The baby of an infected mother may be born with congenital syphilis. In the primary stage of infection, a chancre, or ulceration, develops on the genitals (usually the vulva of the female and the penis of the male). If untreated, the secondary stage of the disease appears as a nonitching rash that affects any part of the body. At this stage, the patient is still infectious. If still untreated, the disease may become dormant for many years before the development of the most serious or tertiary stage of the disease, in which radiographic abnormalities become apparent. The young black male population is most often affected.



Radiographic Appearance


Cardiovascular syphilis involves primarily the ascending aorta, which may become aneurysmally dilated and often demonstrates linear calcification of the wall (Figure 11-1). Syphilitic aortitis often involves the aortic valvular ring and produces aortic regurgitation with enlargement of the left ventricle.




Radiographer Notes


Because of its nonionizing character, ultrasound has become the major modality for imaging both the male and female reproductive systems. Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are used for staging malignant tumors when ultrasound is inconclusive, and radionuclide studies are used to differentiate testicular torsion from epididymitis.


Conventional plain image radiography is virtually never indicated for disorders of the pregnant patient. The once common pelvimetry and gravid uterus examinations have been almost completely replaced by nonionizing ultrasound imaging. The two radiographic studies of the female reproductive system that are in current use are hysterosalpingography and mammography. Hysterosalpingography, which is performed with fluoroscopic guidance, evaluates the patency (openness) of the fallopian tubes. Plain radiographs are obtained only to provide a permanent record. Mammography requires dedicated equipment and a specially trained radiographer. Properly performed mammograms can detect breast cancer in the early stage, before it is symptomatic, thus decreasing the incidence of metastases and greatly improving patient survival rates. However, mammograms performed by poorly trained radiographers or with inadequate equipment may fail to demonstrate early lesions, condemning women with an otherwise curable disease to unnecessary suffering and even death.


It is essential that the radiographer attempt to put the patient at ease when performing an examination of the reproductive system. Although these procedures are not actually painful, they may at times be uncomfortable and are frequently embarrassing for the patient. A good professional attitude goes a long way in reassuring the patient and making these examinations as comfortable as possible.


Syphilitic involvement of the skeletal system most commonly produces radiographic findings of chronic osteomyelitis, which usually affects the long bones and the skull. The destruction of bone incites a prominent periosteal reaction, with dense sclerosis as the most outstanding feature (Figure 11-2). Syphilis is a major cause of neuropathic joint disease (Charcot’s joint), in which bone resorption and total disorganization of the joint are associated with calcific and bony debris (Figure 11-3).




Syphilitic lesions developing in the cerebral cortex can cause mental disorders, deafness, and blindness. The cerebral lesions containing syphilis bacteria (intracerebral gummata) are hypodense on nonenhanced computed tomography (CT). On T1-weighted magnetic resonance imaging (MRI), the lesions appear hypointense or isointense, and they become hyperintense on T2-weighted images. The intracerebral gummata densely enhance with the administration of gadolinium. Single-photon emission computed tomography (SPECT) demonstrates the significant decrease of blood flow in the frontal and temporal cortices bilaterally. Scans obtained following therapy demonstrate a marked improvement in flow. Diffuse thickening of the gastric wall can cause narrowing of the lumen that is indistinguishable from that seen in carcinoma.


Multiple bone abnormalities can occur in infants with congenital syphilis who are born to infected mothers (Figure 11-4). Mental retardation, deafness, and blindness are common complications.





Gonorrhea


Gonorrhea is a bacterial infection, one of the most common and most widespread of the venereal diseases, which occurs more commonly in men (1.5:1). Persons of Asian and Pacific Island descent are least likely affected, whereas the African-American population is experiencing the greatest increase. Symptoms usually occur a few



days after infection. An acute urethritis with copious discharge of pus develops in men. Women may be asymptomatic or may have minimal symptoms of urethral or cervical inflammation. If untreated, the inflammation may become chronic, spread upward, and produce fibrosis, leading to urethral stricture in men (Figure 11-5) and pelvic inflammatory disease (PID) or sterility in women. A serious complication is fibrous scarring of the fallopian tubes that may result in sterility or an ectopic pregnancy.






Male reproductive system



Physiology of the male reproductive system


The major function of the male reproductive system is the formation of sperm (spermatogenesis), which begins at about 13 years of age and continues throughout life. Under the influence of follicle-stimulating hormone (FSH) secreted by the anterior lobe of the pituitary gland, the seminiferous tubules of the testes are stimulated to produce the male germ cells called spermatozoa. In addition to producing sperm cells, the testes secrete the male hormone testosterone. This substance stimulates the development and activity of the accessory sex organs (prostate, seminal vesicles) and is responsible for adult male sexual behavior. Testosterone causes the typical male changes that occur at puberty, including the development of facial and body hair and alterations in the larynx that result in a deepened voice. Testosterone also helps regulate metabolism by promoting growth of skeletal muscles and is thus responsible for the greater muscular development and strength in males.


The final maturation of sperm occurs in the epididymis, a tightly coiled tube enclosed in a fibrous casing (Figure 11-6). The sperm spend about 1 to 3 weeks in this segment of the duct system, where they become motile and capable of fertilizing an ovum. The tail of the epididymis leads into the vas deferens, a muscular tube that passes through the inguinal canal as part of the spermatic cord and joins the duct from the seminal vesicle to form the ejaculatory duct. Depending on the degree of sexual activity and frequency of ejaculation, sperm may remain in the vas deferens up to 1 month with no loss of fertility. Severing of the vas deferens (vasectomy) is an operation performed to make a man sterile. Vasectomy interrupts the route from the epididymis to the remainder of the genital tract.



The seminal vesicles lie on the posterior aspect of the base of the bladder and secrete a thick liquid that is rich in fructose, a simple sugar that serves as an energy source for sperm motility after ejaculation. The seminal vesicles also secrete prostaglandin, which increases uterine contractions in the woman and helps propel the sperm toward the fallopian tubes.


The prostate gland lies just below the bladder and surrounds the urethra. It secretes a thin alkaline substance that constitutes the major portion of the seminal fluid volume. The alkalinity of this material is essential to sperm motility, which would otherwise be inhibited by the highly acidic vaginal secretions.


Intense sexual stimulation causes peristaltic contractions in the walls of the epididymis and vas deferens, propelling sperm into the urethra. At the same time, the seminal vesicles and prostate gland release their secretions, which mix with the mucous secretion of the bulbourethral glands to form semen. The ejaculation of semen occurs when intense muscular contractions of erectile tissue cause the semen to be expressed through the urethral opening.


Male fertility is related not only to the number of sperm ejaculated but also to their size, shape, and motility. Although only one sperm fertilizes an ovum, millions of sperm seem to be necessary for fertilization to occur. Indeed, it is estimated that sterility may result when the sperm count falls below about 50 million per mL of semen.



Benign prostatic hyperplasia


Enlargement of the prostate gland is common in men more than 60 years of age and may be detected on a digital rectal examination. The enlargement is probably related to a disturbance of hormone secretions from the sex glands that occurs as the period of reproductive activity declines. The major effect of prostatic enlargement is an inability to empty the bladder completely, leading to partial urinary tract obstruction, bilateral ureteral dilatation, and hydronephrosis.



Radiographic Appearance


Transrectal ultrasound imaging, performed by means of a probe inserted into the rectum, demonstrates gland enlargement and heterogeneous signal intensity of the central portion (Figure 11-7). A circumferential surgical pseudocapsule, discrete nodules, and a thickened bladder wall may also be visualized. Moreover, an abdominal-pelvic scan can demonstrate residual urine volume and aids in the evaluation of the kidneys for the presence of hydronephrosis.



On excretory urography, the enlarged prostate typically produces elevation and a smooth impression on the floor of the contrast material–filled bladder (Figure 11-8). Elevation of the insertion of the ureters on the trigone of the bladder produces a characteristic J-shaped, or fish-hook, appearance of the distal ureters. Residual urine in the bladder provides a growth medium for bacterial infection, which produces cystitis; the infection may ascend from the bladder to the kidney, resulting in pyelonephritis.



On MR images, benign prostatic hyperplasia causes a diffuse or nodular area of homogeneous low signal intensity on T1-weighted images and an inhomogeneous, mixed (intermediate to high) signal intensity on T2-weighted images (Figure 11-9). A pseudocapsule, representing compression of adjacent tissue visualized as a low–signal intensity rim, often accentuates focal enlargement. Diffuse enlargement shows similar intensity changes, though the pseudocapsule is not present. Unfortunately, the intensity of benign prostatic hyperplasia may often be similar to that of the normal prostate or a region of prostatitis.





Carcinoma of the prostate gland


Carcinoma of the prostate gland is the second most common malignancy in men, with a slightly higher incidence in black men. The disease rarely occurs before 50 years of age, and the incidence increases by about 40% with advancing age. The tumor can be slow growing and asymptomatic for long periods or can behave aggressively with extensive metastases. Prostate carcinoma occurs most often in the peripheral zone (70%). Carcinoma of the prostate is best detected by palpation, on which it is detected as a hard, nodular, and irregular mass, on a routine rectal examination. The presence of an elevated serum PSA (prostate-specific antigen) value indicates an abnormality, though this blood test is not specific for malignancy.



Radiographic Appearance


Radiographically, carcinoma of the prostate often elevates and impresses the floor of the contrast-filled bladder. Unlike the smooth contour seen in benign prostatic hyperplasia, the impression on the bladder floor is usually more irregular in carcinoma (Figure 11-10). Bladder neck obstruction, infiltration of the trigone, or invasive obstruction of the ureters above the bladder may produce obstruction of the upper urinary tract.



Transrectal ultrasound is the preferred technique for detecting carcinoma of the prostate (Figure 11-11). The normal prostate has a generally homogeneous appearance with a moderate echo pattern. Early studies indicated that prostatic carcinoma appeared as hyperechoic areas. However, with the development of newer and higher-frequency transducers, many carcinomas appear as areas of low echogenicity within the prostate. Up to 40% of carcinomas are isoechoic with normal prostate tissue and thus cannot be visualized on ultrasound. The latest studies have concluded that the wide range of sonographic patterns in carcinoma indicates that ultrasound cannot reliably differentiate prostatic malignancy from benign disease.




Staging



Radiographic Appearance


MRI can superbly delineate the prostate, seminal vesicles, and surrounding organs to provide accurate staging of pelvic neoplasms. When the spin-echo technique is used, the central and peripheral zones of the prostate are well demonstrated and distinctly separate from the surrounding levator ani muscles. In the sagittal plane, the relation of the prostate to the bladder, rectum, and seminal vesicles is clearly shown. Prostatic carcinoma is best demonstrated on long TR images, where it appears as disruption of the normally uniform high signal intensity of the peripheral zone of the prostate (Figure 11-12). T2-weighted images demonstrate low intensity that is surrounded by the hyperintense signal of the normal tissue. The new technique of MR lymphography aids in visualizing nonenlarged pelvic lymph nodes. However, there is much controversy over whether MRI is reliable for detection and diagnosis of prostate cancer, and therefore a precise diagnosis requires a biopsy and histologic examination. Research findings state that the demonstration of a normal-appearing prostate gland on MRI does not exclude the presence of a neoplasm. In addition, inhomogeneity of the gland is a common nonspecific finding that can also be seen in patients with adenoma or prostatitis.



Carcinoma of the prostate may spread by direct extension or by way of the lymphatics or the bloodstream. Spread of carcinoma of the prostate to the rectum can produce a large, smooth, concave pressure defect; a fungating ulcerated mass simulating primary rectal carcinoma; or a long, asymmetrical annular stricture. Both ultrasound and CT, especially the arterial phase of multislice CT, aid in defining extension of tumor into the bladder and seminal vesicles and in detecting metastases in enlarged lymph nodes (Figure 11-13).



The most common hematogenous metastases are to bone. They involve primarily the pelvis, thoracolumbar spine, femurs, and ribs. These lesions are most commonly osteoblastic and appear as multiple rounded foci of sclerotic density (Figure 11-14) or occasionally as diffuse sclerosis involving an entire bone (“ivory vertebra”). Patients with bony metastases usually have strikingly elevated serum acid phosphatase values. Because significant bone destruction or bone reaction must occur before a lesion can be detected on plain radiographs, the radionuclide bone scan is the best screening technique for detection of asymptomatic skeletal metastases in patients with carcinoma of the prostate. However, because the radionuclide scan is very sensitive but not specific and may show increased uptake in multiple disorders of the bone, conventional radiography of the affected site should be performed when the scan is abnormal.





Undescended testis (cryptorchidism)


Near the end of gestation, the testis normally migrates from its intraabdominal position through the inguinal canal into the scrotal sac. This condition is more common in premature males and can cause infertility. If one of the testicles cannot be palpated within the scrotum, it is important to determine whether this finding represents absence of the testis or an ectopic position of the testis. The rate of malignancy is up to 40 times higher in the undescended (intraabdominal) testis than in the descended testicle.



Radiographic Appearance


In the absence of a palpable testicle, ultrasound is usually used as a screening technique. This modality carries no radiation risk and has a high diagnostic accuracy in demonstrating undescended testicles that are located in the inguinal canal (Figure 11-15). However, sonography is not successful in detecting ectopic testicles in the pelvis or abdomen. If ultrasound fails to demonstrate an undescended testis, MRI or CT is indicated (Figures 11-16 and 11-17). MRI typically demonstrates a low signal mass on T1-weighted images that has high signal intensity on T2-weighted images. The uniform oval soft tissue mass of an undescended testis demonstrates contrast enhancement on CT.







Testicular torsion and epididymitis


Testicular torsion refers to the twisting of the gonad on its pedicle, which leads to compromise of the circulation and the sudden onset of severe scrotal pain. Although primarily a clinical diagnosis, the scrotal pain and swelling of testicular torsion may be difficult to distinguish from those caused by inflammation of the epididymis (epididymitis). In such cases, color Doppler ultrasound or radionuclide studies are of value.



Radiographic Appearance


The preferred imaging modality for testicular torsion or epididymitis depends on the patient’s age—generally, color Doppler ultrasound in adults and radionuclide studies in children. As new technology improves color and power, Doppler ultrasound is the modality of choice in most cases. Doppler ultrasound demonstrates the presence of intratesticular arterial pulsations. In testicular torsion, the arterial perfusion is diminished or absent (Figures 11-18 and 11-19), whereas in epididymitis there is increased blood flow (Figure 11-20). Similarly, the radionuclide angiogram shows isotope activity on the twisted side that is either slightly decreased or at the normal, barely perceptible level. On the uninvolved side, the perfusion should be normal. When compared with the decreased activity on the involved side, the perfusion appears to be increased. Static nuclear scans demonstrate a rounded, cold area replacing the testicle in patients with torsion (Figure 11-21), but a hot area in those with epididymitis (Figure 11-22). A nuclear testicular scan is superior to Doppler ultrasound for distinguishing between testicular torsion and epididymitis.









Testicular tumors


Testicular tumors are the most common neoplasms in men between 20 and 35 years of age. Almost all testicular tumors are malignant, and they tend to metastasize to the lymphatics that follow the course of the testicular arteries and veins and drain into paraaortic lymph nodes at the level of the kidneys.


There are two major types of testicular tumors. Seminomas constitute about 45% of germ cell tumors; the remaining 55% are nonseminomas that consist of teratomas and other germ cell tumors. Seminomas arise from the seminiferous tubules, whereas teratomas arise from a primitive germ cell and consist of a variety of tissues.



Radiographic Appearance


Testicular tumors are best diagnosed on ultrasound examination (with 98% to 100% accuracy). The normal testis has a homogeneous, medium-level echogenicity. A localized testicular tumor appears as a circumscribed mass with either increased or decreased echogenicity in an otherwise uniform-echo testicular structure. Seminomas appear as uniform hypoechoic masses without calcification or cystic areas (Figure 11-23). A teratoma appears inhomogeneous with cystic and solid areas of calcification and cartilage (Figure 11-24). Testicular tumors can also be detected on MRI (Figure 11-25), which is required when ultrasound findings are equivocal or when there is discrepancy between the ultrasound findings and the physical examination.


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Apr 10, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Reproductive System
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