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RepRoductive ` REPRODUCTIVE—PATHOlOgy RepRoductive ` REPRODUCTIVE—PATHOlOgy SectioN iii 653
Testicular tumors (continued)
Germ cell tumors
Seminoma Malignant Painless, homogenous testicular enlargement. Most common testicular
tumor. Analogous to ovarian dysgerminoma. Does not occur in infancy.
Large cells in lobules with watery cytoplasm and “fried egg” appearance
on histology, placental ALP (PALP). Highly radiosensitive. Late
metastasis, excellent prognosis.
Teratoma May be malignant Unlike in females, Mature teratoma in adult Males may be Malignant.
Benign in children.
Embryonal carcinoma Malignant Painful, hemorrhagic mass with necrosis. Often glandular/papillary
morphology. “Pure” embryonal carcinoma is rare; most commonly
mixed with other tumor types. May present with metastases. May be
associated with hCG and normal AFP levels when pure ( AFP when
mixed). Worse prognosis than seminoma.
Yolk sac (endodermal Malignant, aggressive Yellow, mucinous. Analogous to ovarian yolk sac tumor. Schiller-Duval
sinus) tumor bodies resemble primitive glomeruli. AFP is highly characteristic.
Most common testicular tumor in boys < 3 years old.
Choriocarcinoma Malignant Disordered syncytiotrophoblastic and cytotrophoblastic elements.
Hematogenous metastases to lungs and brain. hCG, may produce
gynecomastia, symptoms of hyperthyroidism (α-subunit of hCG is
identical to LH, FSH, TSH).
Non-germ cell tumors
Sertoli cell tumor Mostly benign Androblastoma from sex cord stroma.
Leydig cell tumor Mostly benign Golden brown color; contains Reinke crystals (eosinophilic cytoplasmic
inclusions). Produces androgens or estrogens gynecomastia in men,
precocious puberty in boys.
Testicular lymphoma Malignant, aggressive Most common testicular cancer in older men. Not a 1° cancer; arises
from metastatic lymphoma to testes.
Hormone levels in germ cell tumors
SEmINOmA yOlK SAC TUmOR CHORIOCARCINOmA TERATOmA EmbRyONAl CARCINOmA
PALP – – – –
AFP – – – –/ (when mixed)
β-hCG –/ –/ –
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