Fibrolamellar Carcinoma

 Uncommon malignant hepatocellular tumor

• Also known as fibrolamellar hepatocellular carcinoma (HCC)
image Distinct clinical, histopathologic, and imaging features differentiate it from conventional HCC

IMAGING

• Heterogeneously enhancing, large, lobulated mass with hypointense central scar and radial septa
image Calcification and necrosis are common (> 50%)
image Nodal metastases (> 50%)
image Vary from 5-20 cm (mean: 13 cm)
image “Satellite” nodules are often present
• Slow-growing tumor that usually arises in normal (noncirrhotic) liver
• Better prognosis than conventional HCC but still locally invasive and frequently metastatic

TOP DIFFERENTIAL DIAGNOSES

• Focal nodular hyperplasia (FNH)
• Conventional HCC
• Hepatic cavernous hemangioma
• Peripheral cholangiocarcinoma

DIAGNOSTIC CHECKLIST

• FLC simulates FNH due to presence of central scar in both tumors
image FLC: Bigger, more heterogeneous mass frequently with calcified central/eccentric scar and features of malignancy (vessel &/or biliary obstruction, nodal invasion, and lung metastases)
image Scar on T2WI: Hypointense in FLC,  hyperintense in FNH
• Large, heterogeneous, hypervascular tumor in young adult
image
(Left) Axial graphic shows a large, heterogeneous, hypervascular mass with a central scar and porta hepatis lymphadenopathy image.

image
(Right) Axial CECT in a 15-year-old boy shows a large, heterogeneous, hypervascular mass image with a large, calcified central scar image and cardiophrenic lymphadenopathy image. In a young person, these findings are essentially diagnostic of fibrolamellar carcinoma (FLC)
image
(Left) Axial CECT of a 22-year-old man with abdominal discomfort and a palpable mass shows a large, heterogeneous, lobulated mass image with a large central scar containing foci of calcification image. Scar calcification is very rare in focal nodular hyperplasia (FNH), by comparison.

image
(Right) Gross pathology of the same patient’s resected tumor shows a well-demarcated, lobulated, heterogeneous tumor with bile staining and central or eccentric fibrous scars image, typical features of FLC.

TERMINOLOGY

Abbreviations

• Fibrolamellar carcinoma (FLC) of liver

Synonyms

• Fibrolamellar hepatocellular carcinoma

Definitions

• Uncommon malignant hepatocellular tumor
image Distinct clinical, histopathologic, and imaging features differentiate it from conventional hepatocellular carcinoma (HCC)

IMAGING

General Features

• Best diagnostic clue
image Heterogeneously enhancing, large, lobulated mass with hypointense central scar and radial septa
• Location
image Intrahepatic (80%)
image Pedunculated (20%)
• Size
image 5-20 cm (mean: 13 cm)
• Key concepts
image Slow-growing tumor that usually arises in normal (noncirrhotic) liver
– May occur with underlying cirrhosis (< 5% of cases)
image “Satellite” nodules are often present
image Characteristic microscopic pattern
– Eosinophilic malignant hepatocytes containing prominent nuclei
image Absence of pathologic markers (e.g., inclusions of α-fetoprotein bodies) that are present in conventional HCC
image Better prognosis than conventional HCC but still locally invasive and frequently metastatic

CT Findings

• NECT
image Mass
– Well-defined contour
– Hypoattenuating and heterogeneous
image Central scar and septa: Markedly hypodense
image Calcification and necrosis are common (> 50%)
image Hemorrhage is rarely seen
• CECT
image Arterial phase
– Mass: Heterogeneous and hyperattenuating (80%)
image Portal phase
– Mass: Iso-/hypoattenuating
image Delayed phase (10 min)
– Mass: Isodense
– Scar and septa: Hyperdense
image Malignant features
– Biliary and vessel invasion
– Nodal metastases (> 50%)
image Porta hepatis and cardiophrenic nodes
– Lung metastases

MR Findings

• T1WI
image Mass: Heterogeneous and slightly hypointense
image Scar and septa: Hypointense
• T2WI
image Mass: Heterogeneous and hyperintense
image Scar and septa: Hypointense
• T1WI C+
image Arterial and portal phases
– Intense heterogeneous enhancement of mass, not scar
image Delayed phase
– Mass: More homogeneous enhancement
– Scar and septa: Delayed partial enhancement

Ultrasonographic Findings

• Grayscale ultrasound
image Mass
– Large, solitary, well defined, and lobulated
– Variable echotexture
image Central scar: Hyperechoic

Angiographic Findings

• Conventional
image Mass
– Hypervascular (neovascularity)
– Enlarged feeding arteries
– Dense tumor blush
– No arterial-venous or arterial-portal shunting

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Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Fibrolamellar Carcinoma

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