What is the hallmark appearance of Fibrolamellar carcinoma?

The hallmark appearance of Fibrolamellar carcinoma is characterized by the presence of fibrous bands within the tumor. This distinctive feature is crucial for pathologists when diagnosing this rare type of liver cancer, especially since it often occurs in younger individuals and can present differently from typical hepatocellular carcinoma.

The fibrous bands are believed to be related to the tumor's unique fibrolamellar subtype, in which collagen-rich stroma is prominent and can create a striking pattern upon microscopic examination. This fibrous stroma contributes to the tumor's distinctive histological appearance, which is vital for differentiating it from other liver tumors.

While other features such as solid and cystic components, hemorrhagic necrosis, or uniform cellularity may occur in various tumors, they do not specifically define Fibrolamellar carcinoma. The identification of fibrous bands is crucial for pathologic diagnosis and is used in the context of its histopathological findings, making this characteristic essential for both surgical pathology and clinical prognosis.