Features of Hepatoblastoma
This tumor is a pathology of early childhood and appears to be congenital in nature. Clinically and laboratory-wise, it is accompanied by an elevation of serum $\alpha$-fetoprotein levels. The disease is frequently associated with various congenital birth defects.
Anatomically, the neoplasm is most commonly localized in the right lobe of the liver. On cut section, the tissue has a characteristic variegated appearance caused by blood-filled vascular spaces, as well as foci of necrosis and hemorrhage.
Histological Structure of Hepatoblastoma
Two main histological variants of this tumor are distinguished:
- Epithelial type — formed by small oval (embryonal) elements and/or light and dark hepatocyte-like (fetal) cells.
- Epithelial-mesenchymal type — in addition to the parenchyma, it is characterized by a well-developed stroma. Islands of osteoid, chondroid (cartilaginous), and muscular tissue are found within this stroma.
Hemangiosarcoma and Risk Factors
Malignant vascular tumors of the liver, specifically hemangiosarcoma (hepatic angiosarcoma), are most commonly diagnosed in elderly men. Macroscopically, the organ contains multiple reddish nodules that lack clear boarders.
Specific risk factors and background conditions contribute to the development of this tumor:
- Liver cirrhosis.
- Exposure to Thorotrast.
- Exposure to arsenic.
- Exposure to vinyl chloride monomer.
Microscopic Appearance of Vascular Tumors
Histologically, malignant vascular neoplasms of the liver vaguely resemble cavernous hemangioma, but possess several severe distinguishing features.
Under the microscope, numerous vascular spaces lined by elongated cells and areas of solid architecture are identified. The main sign of malignancy is marked cellular atypia: pronounced polymorphism, bizarre-shaped cells, multinucleated structures, and numerous atypical mitotic figures are recorded.