Yolk Sac Tumour
Gross features:
- Nonencapsulated
- Cut section:
homogeneous, yellow-white, mucinous
Histologic features:
- Reticular network
of medium-sized cuboidal or elongated cells
- Often foamy, lacy
appearance
- May have papillary
structures or solid cords of cells
- 50% have
Schiller-Duval bodies; structures resembling endodermal
sinuses
- mesodermal core with a central capillary
- a visceral and
parietal layer of cells resembling primitive glomeruli
- eosinophilic, hyaline-like cytoplasmic
and extracytoplasmic globules which stain for AFP and alpha-1-antitrypsin
- 1 to 50 microns
- uncommon in seminoma and embryonal
carcinoma
- multiple patterns:
- endodermal sinus (perivascular
/ festoon)
- Schiller-Duval
bodies
- Fibrous cores
of tissue draped (festooned) by tumour cels forming labyrinthine spaces
- Reticular (most
common)
- Network of tumour cells with prominent cytoplasmic
vacuolation
- Microcystic or honeycomb appearance
- Macrocystic
- Papillary
- Cystic spaces
with papillary processes projecting within
- Solid
- Sheetlike
- Lacking fibrous
septations and lymphocytes of seminoma
- Glandular-alveolar
- Cystic,
alveolar-like spaces lined by flattened epithelium
- Often enteric
features with an apical brush border
- May see:
- subnucleolar vacuolation
- myxomatous
- trabeculae, thin cords, and individual cells in a mucoid stroma
- high
hyaluronic acid content
- may see:
- stromal
differentiation into skeletal muscle, cartilage
- polyvesicular vitelline
- vesicles lined
by flattened to cuboidal to columnar cells
- often central constriction
of vesicles
- columnar cells
resemble primitive enteric epithelium
- apical and
basal vacuoles may be seen
- hepatic
- hepatoid cells in sheets, trabeculae, or nests
- parietal (scattered
foci seen in 92% of cases)
- confluent
deposits of extracellular basement membrane
between neoplastic cells
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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AFP (often patchy)
|
Highly characteristic
|
Other GCT’s
negative
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Alpha-1-antitrypsin
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Molecular features:
Other features:
References: