IUHS Student-2-Student USMLE Step 1 Recall

                                                    Reproduction

                                          Male Reproductive Organs

Balanoposthitis

refers to infection of the glans and prepuce caused by a wide variety of organisms...

most common infections are by staph and strep...

among the more common agents are candida albicans, anaerobic bacteria, gardnerella, and pyogenic bacteria....

most cases occur as a consequence of poor local hygiene in uncircumcised males, with accumulation of desquamated epithelial cells, sweat, and debris, termed smegma, acting as local irritant...

persistance of such infections leads to inflammatory scarring and, as mentioned earlier, is a common cause of phimosis...

Phimosis occurs when the orifice of the prepuce (foreskin) is too small to permit normal retraction...this may be due to inflammatory scarring or abnormal devleopment of the prepuce...can cause development of penile squamous intraepithelial neoplasia...

if a phimotic prepuce is forcibly retracted over the glans penis, a condition called paraphimosis may develop...this condition is extrememly painful and may cause obstuction of the urinary tract or blood flow, which may lead to necrosis of the penis...

Cryptorchidism

cryptorchidism is synonymous with undescended testes and is found in approximately 1% of 1 year old boys...this anomaly represents a complete or incomplete failure of the intra-abdominal testes to descend into the scrotal sac...

it usually occcurs as an isolated anomaly but may be accompanied by other malformations of the genitourinary tract, such as hypospadias...

testicular descent occurs in two morphologically and hormonally distinct phases...during the first, transabdominal, phase, the testis comes to lie within the lower abdomen or brim of the pelvis...this phase is believed to be controlled by a hormone called mullerian-inhibiting substance...

in the second, or the inguinoscrotal, phase, the testes descend through the inguinal canal into the scrotal sac...this phase is androgen dependent and is possibly mediated by androgen induced release of calcitonin gene related peptide, from the genitofemoral nerve...

it is unilateral in the majority of caes...the testis is small, brown, and strophic grossly...

microscopically, the tubules are atrophic with thickened basement mebranes...the interstitial cells are usually prominent and occasional focal proliferations of sertoli cells may be seen...the incidence of malignancy is increased 7-11 fold, and this risk is greater for abdominal than for inguinal locations...seminomas...

if not realized until adulthood, great chance for seminoma to develop, thus should be removed instead of surgical desention....

Seminoma Testicular Tumor

seminomas are the most common type of germinal tumor (50%) and the type most likely to produce a uniform population of cells...

highly radio-sensitive...chemosensitive...late metastasis...excellent prognosis...

seminomas "seminoles" are radio sensitive...

they almost never occur in infants; they peak in the thirties, somewhat later than the collective peak...

a nearly identical tumor arises in the ovary, where it is called dysgerminoma...

Tumor Marker: Placental alkaline phosphatase (PLAP)...

the typical seminoma has a homogeneous, gray-white lobulated cut surface, usually devoid of hemorrhage or necrosis...

polygonal germ cells with clear cytoplasm and round nuclei...arranged in lobules, which are separated by fibrous septate...lymphocytes, granulomas, and giant cells may be seen...

in more than half the cases, the entire testis is replaced...generally the tunica albuginea is not penetrated, but occasionally extension to the epididymis, spermatic cord, or scrotal sac occurs...

the classic seminoma cell is large and round to polyhedral and has a distinct cell membrane; a clear or watery appearing cytoplasm; and a large central nucleus with one or two prominent nucleoli...

Spermatocytic Seminoma

spermatocytic seminoma is a uncommon tumor, representing 1-2% of all testicular germ celll neoplasms...

the age of involvement is much later than for most testicular tumors...affected individuals are generally over the age of 65 years...

in contrast to classic seminoma, it is slow-growing tumor that rarely if ever produces metastases, and hence the prognosis is excellent...

grossly, spermatocytic seminoma tends to be larger than classic seminoma and presents with a pale gray, soft, and friable cut surface...

with the electron microscope, tumor cells show nuclear and cytoplasmic features of spermatocytic maturation, thus justifying the term spermatocytic seminoma...

beta-HCH is elevated and LDH levels are elevated...

Embryonal Carcinoma of the Testis

alpha-Fetoprotein elevated...

may also have beta-HCG elevated...

embryonal carcinomas occur mostly in the 20-30 year age group...these tumors are more aggressive than seminomas...

grossly, the tumor is smaller than seminoma and usually does not replace the entire testis...on cut surfaces, the mass is often variegated, poorly demarcated at the margins, and punctuated by foci of hemorrhage or necrosis...

extension through the tunica albuginea into the epididymis or cord is not infrequent...

histologically the cells grow in glandular, alveolar, or tubular patterns, sometimes with papillary convolutions...more undifferentiated lesions may present sheets of cells...

the neoplastic cells have an epithelial appearance and are large and anaplastic, with angry-looking hyperchromatic nuclei having prominent nucleoli...in contrast to seminoma, the cell borders are usually indistinct, and there is considerable variation in cell and nuclear size and shape...

mitotic figures and tumor giant cells are frequent..within this background, syncytial cells containing HCG or cells containing AFP, or both, may be detected by immunoperoxidase techniques...b/c HCG and AFP are products of trophoblastic and yolk sac cells respectively, their presence is indicative of a mixed tumor...

if tumors containing HCG or AFP, or both, are excluded,  it is estimated that pure embryonal cell carcinomas constitute about 3% of testicular germ cell tumors...if one includes mixed tumors, however, embryonal carcinoma cells are present in about 45% of tumors...

AFP is seen only in nonseminomas...the half life of AFP is 5-7 days...

Yolk Sac Tumors (endodermal sinus tumor)

also known as infantile embryonal carcinoma or endodermal sinus tumor, the yolk sac tumor is of interest because it is the most common testicular tumor in infants and children up to 3 years of age, and in this age group it has a very good prognosis...Micro: Schiler-Duval Bodies...

in adults, the pure form of this tumor is rare; instead, yolk sac elements frequently occur in combination with embryonal carcinoma...

grossly, the tumor is nonencapsulated, and on cross-section it presents a homogeneous, yellow-white, mucinous appearance...

charactersitic on examination is a lacelike (reticular) network of medium sized cuboidal or elongated cells...in adddition, papillary structures or solid cords of cells may be found...in approximately 50% of tumors, the so called endodermal sinuses may be seen; these consist of a mesodermal core with a central capillary and a visceral and parietal layer of cells resembling primitive glomeruli...

present within and outside the cytoplasm are eosinophilic, hyalin-like granules in which AFP and alpha1-antitrypsin can be demonstrated by immunocytochemical staining...

the presence of AFP in the tumor cells is highly characteristic, and it underscores their differentiation into yolk sac cells...

AFP elevation is seen only in nonseminomas...the half life of AFP is 5-7 days...

Choriocarcinoma in relation to Testicular Cancers

choriocarcinoma is a highly malignant (with widespread metastasis) form of testicular tumor that is composed of both cytotrophoblast and syncytiotrophoblast...

hematogenous spread to lungs and liver...

testicular enlargement and gynecomastia...b/c of b-hcg...

identical tumors may arise in the placental tissue, ovary, or sequestered rests of totipotential cells...in its pure form, choriocarcinoma is rare, constituting less than 1% of all germ cell tumors...

despite their aggressive behavior, pure choriocarcinomas are usually small lesions...often they cause non testicular enlargement and are detected only as a small palpable nodule...

b/c they are rapidly growing, they may outgrow their blood supply, and sometimes the primary testicular focus is replaced by a small fibrous scar, leaving only widespread metastases...typically, these tumors are small, rarely larger than 5cm in diameter...

hemorrhage and necrosis are extremely common....histologically the tumors contain two cell types...

the syncytiotrophoblastic cell is large and has many irregular or lobular hyperchromatic nuclei an an abundant eosinophilic vacuolated cytoplasm....

as might be expected, beta-HCG can be readily demonstrated in the cytoplasm of syncytiotrophoblastic cells...the cytotrophoblastic cells are more regular and tend to be polygonal with distinct cell borders and clear cytoplasm; they grow in cords of masses and have a single, fairly uniform nucleus...

beta-HCH is elevated and LDH levels are elevated...

AFP elevation is seen only in nonseminomas...the half life of AFP is 5-7 days...

Testicular Teratomas

the designation teratoma refers to a group of complex tumors having various cellular or organoid components reminiscent of normal derivatives from more than one germ layer...99% are malignant...

often cystic masses contain cartilage and bone...Micro: contains ectoderm, endoderm, and mesodermal tissue in a haphazard arrangement...

they may occur at any age from infancy to adult life...pure forms of teratoma ar fairly common in infants and children, second only in frequency to yolk sac tumors...

in adults, pure teratomas are rare, constituting 2 to 3% of germ cell tumors...as with embryonal carcinomas, their frequency in combination with other histologic types is about 45%...

in the child, differentiated mature teratomas may be expected to behave as benign tumors, and almost all these patients have a good prognosis...

in the adult, it is difficult to be certain b/c, as pointed out, even apparently differentiated mature teratomas may harbor minute foci of cancer and should therefore be treated as malignant tumors...

beta-HCH is elevated and LDH levels are elevated...

AFP elevation is seen only in nonseminomas...the half life of AFP is 5-7 days...

Mixed Tumors of Testis

about 60% (most common testicular tumor) of testiuclar tumors are composed of more than one of the pure patterns...the most common mixture is that of teratoma, embryonal carcinoma, yolk sac tumor, and HCG-containing syncytiotrophoblast...

tumors with such a combination constitute 14% of testicular germ cell tumors...other combinations include seminoma with embryonal carcinoma and embryonal carcinoma with teratoma...the latter has been called teratocarcinoma...

in most instances, the prognosis is worsened by the inclusion of more aggressive elements (the teratoma with a focus of choriocarcinoma has  poorer outlook than that of pure teratoma)...

beta-HCH is elevated and LDH levels are elevated...

AFP elevation is seen only in nonseminomas...the half life of AFP is 5-7 days...

Cysts in the Tunica Vaginalis of the Testes

scrotal enlargement may be caused by cysts, tumors, inflammatory processes, or abnormalities of the blood vessels...transillumination is helpfull in differentiation between cysts (which transilluminate) and tumors (which do not)...

recall that the processus vaginalis is an outpouching of the peritoneum that enters into the scrotum...when the testis reaches the scrotum, the proximal portion of the processus vaginalis obliterates, but the distal portion persists and does not fuse...

this forms the tunica vaginalis of the testis...examples of cysts that involve this tunica vaginalis include hydroceles, hematoceles, chyloceles, and spermatoceles...

hyrdoceles contain clear fluid and result from developmental abnormalities or inflammatory processes...transillumination is present...

hematoceles result form hemorrhage into a hydrocele, while chyloceles result from the accumulation of lymph fluid within the tunica as a result of elephantiasis...

spermatoceles refer to cystic enlargements of the efferent ducts or the rete testis with numerous spermatocyts present...

Varicocele - dilated vein within the spermatic cord...may cause infertility...block left renal vein...

Spermatocele - dilated efferent duct in the epididymus containing sperm...shortened spermatic cord...loss of cremesteric reflex...contraction of scrotum when stimulated...

Benign Prostatic Enlargement

nodular hyperplasia, still referred to by the redundant term benign prostatic hyperplasia is an extremely common disorder in men over age 50...

it is characterized by

prostatic hyperplasia of stromal and glandular cells, resulting in the formation of large, fairly discrete nodules in the

periurethral region of the prostate...

when sufficiently large, the nodules compress and narrow the urethral canal to cause partial, or sometimes virtually complete, obstruction of the urethra...

dihydrotestosterone (DHT), a metabolite of testosterone, is the ultimate mediator of prostatic growth...it is synthesized in the prostate from circulating testosterone by the action of the enzyme 5alpha-reductase, type 2...

this enzyme is localized principally in the stromal cells, and hence these cells are the main site for the synthesis of DHT...once synthesized, DHT can act in an autocrine fashion on the stromal cells or in paracrine fashion by diffusing into nearby epithelial cells...in both of these cell type, DHT binds to nuclear androgen receptors and signals the transcription of growth factors that are mitogenic to the epithelia and stromal cells...

although testosterone can also bind to the androgen receptors and cause growth stimulation, DHT is ten times more potent b/c it dissociated from the androgen receptor more slowly...

the importance of DHT in causing nodular hyperplasia is supported by clinical observations in which an inhibitor of 5alpha-reductase was given to men with this condition...

therapy with 5alpha-reductase inhibitor markedly reduces the DHT content of the prostate, and in a proportion of cases, there is a decrease in prostatic volume and urinary obstruction...

careful studies have demonstrated that nodular hyperplasia of the prostate originates almost exclusively in the inner aspect of the prostate gland, in the transitional and periurethral zones...

symptoms of nodular hyperplasia, when present, relate to two secondary effects (1) compression of the urethra with difficulty in urination and (2) retention of urine in the bladder with subsequent distention and hypertrophy of the bladder, infection of the urine, and development of cystitis and renal infections...

patients experience frequency, nocturia, difficulty in starting and stopping the stream of urine, overflow dribbling, and dysuria (painful micturition)...

in many cases, sudden acute urinary retention appears for unknown reasons and persists until the patient receives emergency catherterization...

in addition to these difficulties in urination, prostatic enlargement results in the inability to empty the bladder completely...presumably, this inability is due to the raised level of the urethral floor so that, at the conclusion of micturition, a considerable amount of residual urine is left...this residual urine provides a static fluid that is vulnerable to infection...

many secondary changes occur in the bladder, such as hypertrophy, trabeculation, and diverticulum formation...hydronephrosis or acute retention, with secondary urinary tract infection and even azotemia or uremia, may develop...

finally, it should be noted that despite earlier claims that nodular hyperplasia predisposes to cancer of the prostate, most studies deny any association, and hence nodular hyperplasia is not considered to be a premalignant lesion...

Carcinoma of the Prostate

carcinoma of the prostate is the most common form of cancer in men (followed closely by lung cancer) and the second leading cause of cancer death...

it is estimated that more than 300,000 new cases are detected every year, of which approximately 41,000 prove to be lethal...

in addition to these lethal neoplasms, there is an even more frequent anatomic form of prostatic cancer in which a microscopic focus of cancer is discovered as an incidental finding, either at postmortem examination or in a surgical specimen removed for other reasons...

high bound PSA...

low free PSA...

several risk factors, such as age, race, family history, hormone levels, and environmental influences, are suspected of playing roles...

increased consumption of fats has been implicated...it has been proposed that dietary fat intake influences the levels  of hormones such as testosterone, which, in turn, affect the growth of prostate...

other dietary factors, such as intake of vitamin A and beta-carotene are also under scrutiny...

as with nodular hyperplasia of prostate, androgens are believed to play a role in the pathogenesis of prostate cancer...support for this general thesis lies in the inhibition of these tumors that can be achieved with orchiectomy...

neoplastic epithelial cells, similar to their normal counterparts, possess androgen receptors, which suggests that they are responsive to these hormones...

in approximately 70% of cases carcinoma of the prostate arises in the peripheral zone of the gland, classically in a posterior location, often rendering it palpable on rectal examination....

characteristically, on cross section of the prostate, the neoplastic tissue is gritty and firm, but when embedded within the prostatic substance, it may be extremely difficult to visuallize and be more readily apparent on palpation...

microscopic appearance of small, crowded glands containing cells with prominent nucleoli in the nuclei...

comes to clinical attention usually b/c of urinary symptoms, such as difficulty in starting or stopping the stream, dysuria, frequency, or hematuria...

pain is a late finding, reflecting involvement of capsular perineurial spaces....

some patients come to attention b/c of back pain caused by vertebral metastases...the finding of osteoblastic metastases in bone is virtually diagnostic of this form of cancer in men...

high serum alkaline phosphatase...