Pathology of testes and penis

Question 1

Hypoplasia

Answer 1

• Due to defective or incomplete development
• Hypocellular seminiferous epithelium largely reflecting deficiency of germ cell number and spermatogenesis
• Very common cause is cryptorchidism (undescended testicle), pathology is seen in 2yo uncorrected children
• Testicular hypoplasia also seen in androgen insensitivity syndrome, primary or secondary hypogonadism, and klinefelter’s syndrome

Question 2

Cryptorchid testis

Answer 2

• Hypocellular seminiferous tubules and epithelium w/ very thickened BM filled w/ hyaline material
• Cryptorchid testis tend to be small w/ expanded interstitium

Question 3

Klinefelter syndrome (47, XXY)

Answer 3

• One of the most common cause of hypogonadism in males
• Pts are phenotypic male but have small testes and eunuchoid proportions, may have gynecomastia and mental retardation
• At puberty testes fail to develop leading to hyalinization of seminal tubules, failure of germinal epithelium to develop, large clumps/nodules of leydig cells, and high levels of gonadotropins
• Klinefelter can cause sertoli-only syndrome

Question 4

Testicular atrophy

Answer 4

• Causes: ischemia, pituitary dysfxn, orchitis (mumps), radiation, chemoRx, etoh cirrhosis (due to direct toxicity from etoh and cirrhosis leads to inability of liver to metabolize estrogens), excess estrogens or antiandrogens, exogenous androgens
• Histo: leydig cell nodules (not at large as klinefelter’s), hyalinization of seminiferous tubules (tubules very large), and non-hyalinized tubules w/ atrophic spermatic epithelium

Question 5

Germ cell tumors of the testes

Answer 5

• Make up 95% of testicular tumors, can be seminomatous (seminomas, 50% of germ cell tumors) or non-seminomatous (embryonal CA, yolk sac tumor, choriocarcinoma, teratoma
• Markers: AFP and hCG are usually elevated in nonseminomas (LDH may be elevated in advanced disease)
• All germ cell tumors arise from intratubular germ cell neoplasia (ITGCN), or CIS

Question 6

Seminoma

Answer 6

• Neoplastic cell is an epithelial germ cell of the seminiferous tubule
• Gross: buldging, grey/white lobulated and homogenous, +/- necrosis, tunica albiguinea usually intact
• Micro: monotonous cells resembling germ cells (uniform, clear cytoplasm) arranged in sheets and nests supported by thin fibrous trabeculae +/- inflammation and granuloma formation

Question 7

Embryonal CA and teratoma

Answer 7

• Embryonal CA is of epithelial origin, is very aggressive (invades tunica albiguinea early) and presents w/ very high AFP
• Gross: grey/white w/ necrosis and hemorrhage + invasion of surrounding structures
• Micro: sheets of primitive epithelial cells w/ many mitoses and necrosis, may form tubular/glandular or reticular patterns (cells are large w/ hyper chromatic nuclei)
• Teratoma: common in young children (contains all 3 germ layers) and more often malignant in post pubertal males
• Gross: multicystic, cysts contain gelatinous/cheesy material
• Micro: disordered array of mature and/or immature tissues (can be any of the 3 layers)

Question 8

Yolk sac tumor and choriocarcinoma

Answer 8

• Yolk sac tumor: common in children under 3
• Gross: solid, fleshy, soft and friable
• Micro: reticular pattern (lace-like) w/ schiller-ducal bodies (central capillary w/ visceral and parietal cell layers around it)
• Contain AFP+ hyaline globules
• Choriocarcinoma: small tumor composed of syncytiotrophoblasts and cytotrophoblast cells
• Gross: hemorrhagic mass w/ white/grey tumor only at periphery, may regress leaving a pigmented scar on testes
• Micro: composed of syncytiotrophoblasts (large, multinucleate w/ eosinophilic vacuolated cytoplasm) and cytotrophoblasts (sheets or cords of monomorphic epithelial cells w/ pale cytoplasm), stains positive for hCG

Question 9

Gonadal stromal (non-germinal) tumors (sertoli and leydig)

Answer 9

• These are both rare
• Leydig (interstitial) cell tumor: usually benign, may produce androgen and lead to premature MSK development and precocious enlargement of penis
• Gross: small, well circumscribed yellow-brown
• Histo: sheets of monomorphic leydig cells w/ crystalloids of reinke (eosinophilic globules)
• Sertoli cell tumor: may produce estrogen and lead to gynecomastia
• Gross: solid and firm, circumscribed, pale yellow
• Micro: tubules lined or filled w/ epithelium resembling developing testes

Question 10

Penile CA

Answer 10

• Occurs primarily in tropical climates, almost exclusively in uncircumscribed men, usually >60, associated w/ HPV (mostly type 16 and 18)
• Sx: non-healing sore on foreskin or glans, may be mistaken for STD
• Almost always a SCC, can present first as CIS (erythroplasia of queyat- red area on glans) or bowen disease (crusted plaque on shaft)
• Progresses to invasive CA w/ ulceration or lesion formation
• Micro: SCC