| | Subtype/definition |
| Epithelial |
| Fetal | - Well differentiated and uniform (10-20 µm diameter), round nuclei, cords with minimal mitotic activity, EMH
- Crowded or mitotically active (>2 per 10 400x microscopic fields); conspicuous nucleoli (usually less glycogen)
- Pleomorphic, poorly differentiated
Moderate anisonucleosis, high N/C, nucleoli - Anaplastic with marked nuclear enlargement and pleomorphism, hyperchromasia, abnormal mitoses
|
| Embryonal | - 10-15 µm diameter, high N/C, angular, primitive tubules, EMH
|
| Macrotrabecular | - Epithelial HB (fetal or embryonal) growing in clusters of >5 cells between sinusoids
|
| Small cell undifferentiated (SCU) | - (5-10 µm diameter) no architectural pattern, minimal pale amphophilic cytoplasm, round to oval nuclei with fine chromatin and inconspicuous nucleoli, +/– mitoses; +/– INI*
|
| Cholangioblastic | - Bile ducts, usually at periphery of epithelial islands, can predominate
|
| Mixed |
| Stromal derivatives | - Spindle cells (blastema), osteoid, skeletal muscle, cartilage
|
| Teratoid | - Mixed, plus primitive endoderm; neural derivatives, melanin, squamous and glandular elements
|
