Definition
- Composed of primitive germ cells arranged in various patterns, which can recapitulate the yolk sac, allantois, and extra-embryonic mesenchyme and produce alpha-fetoprotein.
Frequency
- 2%
Histopathology
- Macroscopic
- Solid
- Greyish tan
- Friable (extensive myxoid change) or gelatinous in consistency
- Focal haemorrhage
- Microscopic
- Primitive looking epithelial cells (meaning they came from yolk sac endoderm) arranged in reticular pattern or around anastomosing sinusoidal channels forming papillae called schiler duval bodies
- Tumour cells are small, with non-prominent nucleoli and
scant cytoplasm - Set in a loose, variably cellular, and often myxoid matrix resembling extraembryonic mesoblast.
- Eccentrically constricted cysts delimited by flattened epithelial elements (termed ‘polyvesicular vitelline pattern’), enteric-type glands with goblet cells, and foci of hepatocellular differentiation (termed ‘hepatoid variant’).
- Brightly eosinophilic, periodic acid-Schiff-positive, and diastase-resistant hyaline globules
- Mitosis varies
- Necrosis rare
(A) Typical sinusoidal growth pattern.
(B) Schiller–Duval body and numerous mitoses.
(C) Reticular growth pattern with numerous hyaline globules.
(D) Alpha-fetoprotein immunolabelling.
Immunophenotype
- +
- Consistent
- Alpha feto protein (Cytoplasmic)
- Shared by teratomas also
- Cytokeratins (glypican-3)
- Epithelial cells
- PLAP
- Epithelial cells
- LIN28A
- SALL4 (nuclear)
- Inconsistent
- OCT4
- KIT (focal cytoplasmic rather than membranous
- -
- Beta-hCG
- Human placental lactogen
Blood markers
- Alpha-fetoprotein (MOST)
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