Case 48 - Discussion

Uploaded: 2007-05-26, Updated: 2007-07-26
   
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PLAP

Vimentin

CD30 CD30

 
CK AE1/3  
 

Electron Microscopy

  • Ultrastructurally, the tumor cells are large, polygonal in close apposition. The cytoplasm contains copious amount of glycogen with a background of free ribosomes. The nucleus/cytoplasm ratio is high, ad the nucleus displays finely disperse chromatin. No glandular structures or syncytiotrophoblasts are seen.  

Cytogenetics

  • Hyperpentaploidy clone with  duplication of 1q and 11q, loss of 2, 4, 9, 13, 14 and15.

 
 

Mixed Germ Cell Tumors

 

Pathologic Classification of Common Testicular Tumors

 

Germ Cell Tumors

  • Intratubular germ cell neoplasia

  • Seminoma

  • Spermatocytic seminoma

  • Embryonal carcinoma

  • Yolk sac (endodermal sinus) tumor

  • Choriocarcinoma

  • Teratoma

  • Mixed germ cell tumor

Sex Cord-Stromal Tumors

  • Leydig cell tumor

  • Sertoli cell tumor

  • Granulosa cell tumor

Mixed Sex Cord-Stromal  and Germ cell Tumors

  • Gonadoblastoma

Hematopoietic Tumors

  • Lymphoma

  • Plasmacytoma

  • Leukemia

General Features of Germ Cell Tumors
 

  • Precursor of GCTs: Intratubular germ cell neoplasia; GCTs without precursor: Spermatocytic seminoma and teratoma in infant;

  • Risk factors: (1) cryptorchidism, (2) testicular dysgenesis, and (3) genetic factors;

  • Lymphatic spread to retroperitoneal para-aortic nodes firstly;

  • Approximately 60% of testicular germ cell tumors are mixed type;

  • Approximately 95% of the testicular tumors arise from germ cells;

  • Most of these germinal tumors are highly aggressive cancers that are capable of rapid, wide dissemination, although with current therapy, most can be cured.
 

Seminoma

Clinical Futures
 

  • Most common type of germinal tumor (50%), = female dysgerminoma;

  • Mean age 40 years, rare in infants;

Gross Findings
 

  • Homogeneous, gray-white, lobulated cut surface, usually no hemorrhage or necrosis; may occupy the entire testis;

Microscopic Findings
 

  • Typically, tumor presents sheets of uniform cells divided into poorly demarcated lobules by delicate septa of fibrous tissue;

  • 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; mitoses vary in frequency;

  • Occasional syncytiotrophoblasts seen in 15% cases.

  • The amount of stroma in typical seminomas varies greatly. The septa are usually infiltrated with T lymphocytes;

  • Intratubal germ cell neoplasia (ITGCN) is commonly seen in adjacent normal tissue.

Subtypes
 

Anaplastic seminoma

  • Greater cellular and nuclear irregularity with more frequent tumor giant cells and many mitoses;

  • Not associated with a worse prognosis compared with classic seminoma.

Immunohistochemistry Straining
 

  • Positive: PLAP, OCT4 and CD117. Keratin may be scattered positive;

  • Negative: AFPand HCG;

  • The cytoplasm contains varying amounts of glycogen.

Cytogenetics

  • isochromosome of the short arm of chromosome 12, i(12p);

  • One of the candidate genes, DAD-R, prevents apoptosis.

Reference
 

  • Robbins & Cotran Pathologic Basis of Disease Online