Pathology of Testicular Tumors
Intratubular Germ Cell Neoplasia
The *in situ lesion of a germ cell tumor*, basically atypia of the germ cells and causes predisposition to neoplasia
Yolk Sac Tumors
Also termed *Endodermal Sinus Tumor*; most common germ cell tumor in *children* -Show *Schiller-Duval Bodies* -Make significant *AFP*
Testicular Teratomas
Contain all 3 germ layers; *mostly found in kids/infants*; classified into: 1. Mature Teratomas 2. Immature Teratomas 3. Malignant Teratomas
Genetics of Germ Cell Tumors
Defect on the *short arm of chromosome 12* is present in some 90% of testicular germ cell tumors
Equivalent of Mature Teratomas in Females are _____
Dermoid cysts
Leydig Cell Tumors
Golden brown color; contains *Reinke crystals* (eosinophilic cytoplasmic inclusions). Produce androgens (testosterone) or estrogens -> gynecomastia in men, precocious puberty in boys
Mixed Germ Cell Tumors
Half of the germ cell tumors exhibit more than one type of neoplastic germ cells; most frequent patterns are: 1. Teratoma with Embryonal (Teratocarcinoma) 2. Teratoma, Embryonal and Seminomas 3. Embryonal and Seminoma
Choriocarcinoma
Highly malignant testicular tumor, which represents germ cell extraembryonic differentiation to the components of the placenta (cyto and syncytiotrophoblast) -Cut surface contains marked hemorrhage and necrosis -Secretes *bHCG*
Immature and Malignant Teratomas
Malignant subtype teratomas; demonstrates the same arrangement as a mature teratoma, but the tissues are less differentiated, and more primitive -> more cancerous -> *age of PT* determines severity (older=bad)
Embryonal Carcinoma of Testis
Malignant tumor of the primitive glandular cells; second most common germ cell tumor, much more deadly than seminoma; tunica albuginea and epididymis are invaded -Tumor markers (bHCG, AFP) may be positive due to *mixing with other neoplasia* -Usually has metastasized before detection
Histogenesis of Germ Cell Tumors
One cell type involved: seminoma (most common); Many cell types: if somatic -> teratoma; if extraembryonic -> yolk sac or choriocarcinoma
Seminomas
One cell type involved; *boselated* upon cutting entire testis is replaced by tumor in over half the cases, which appears yellow-white -Exquisitely *sensitive to radiation*
Germ Cell Tumors
Originate from the neoplastic transformation of germ cells and reflect their capacity to differentiate along many histogenetic lines -Risk factors: FH, gonadal dysgenesis, prior dx of germ cell tumor in contralateral testis, cryptorchidism, Klienfelter's
Mature Teratoma
*Benign* teratoma subtype; solid and multicystic lesion that enlarges the testis. The cut surface exhibits mucinous cysts, with solid cartilaginous and osseous foci