¡mSlide 74.¡nYolk sac tumor (endodermal sinus tumor), Testis

A. Brief Descriptions¡G

  1. A neoplasm composed of pure yolk sac elements ,is the most common tumor of infancy.

  2. Yolk sac tumors of infancy have a good prognosis.

B. Gross Findings¡G

    A soft consistency and a microcystic appearance on cross section.

C. Micro Findings¡G

  1. Intermingling of epithelial and mesenchymal elements in a characteristic organoid fashion.

  2. Microcystic, glandular-alveolar, and papillary formation.

  3. Many cystic spaces lined by a very flattened, endothelial-like layer of cells.

  4. The stroma can be quite cellular, spindle shaped cells or myxoid.

  5. Perivascular Schiller-Duval bodies are the most distinctive feature:

    • papillary projections covered by two distinct cell layers separated from each other by a delicate fluorovascular stroma.

  6. Hyaline intracytoplasmic or extracytoplasmic round inclusions.

    • eosinophilic, PAS stain positive and diastase resistance.

    • immunocytochemistry forá -fetoprotein.

D. Others:

  1. Developed teratoma mimicking embryonal yolk sac tissue.

  2. Elevated serum £\ -fetoprotein (tumor marker).

  3. Two distinct circumstances:

    • A pure form - with the classic organoid appearance (described by Teilum) in infants and children, with an excellent prognosis.

    • A component of a mixed germ cell tumor in adults, with a lesser differentiated and more malignant appearance, and worse prognosis.

E. Reference¡G

     Robbins Pathologic Basis of Disease, 6th ed.  P.1075-1076.

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¡i Fig. 74-1 (2X)¡jTumor cells in cystic pattern.

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¡i Fig. 74-2 (2X)¡jPapillary pattern with Schiller-Duval bodies.

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¡i Fig. 74-3 (4X)¡jPerivascular Schiller-Duval bodies are the most distinctive feature.

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¡i Fig. 74-4 (4X)¡jPerivascular Schiller-Duval bodies are the most distinctive feature.Intracytoplasmic and extracytoplasmic inclusion bodies are seen.

 

 

¡i Fig. 74-5 (10X)¡jIntracytoplasmic and extracytoplasmic inclusion bodies are seen.

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¡i Fig. 74-6 (40X)¡jHyperchromatic cancer cells in solid pattern.