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Liver and intrahepatic bile ducts - Tumor

Benign tumors

Focal nodular hyperplasia (FNH)

Reviewers: Deepali Jain, M.D. (see Reviewers page)
Revised: 13 May 2013, last major update February 2012
Copyright: (c) 2004-2013, PathologyOutlines.com, Inc.


● Common benign mass with an indolent course (#2 liver tumor after hemangioma); no known malignant potential
● Usually an incidental finding; present in 1% of autopsies
● Median age 38 years; F:M ratio varies from 8-12:1
● Represents 2-10% of pediatric hepatic tumors; never reported in elderly
● May be associated with oral contraceptives (66-95% of cases), hepatic cavernous hemangioma (20%), glycogen storage disease type Ia, portal hypertension
● Tumors associated with oral contraceptives often have hemorrhage, necrosis, infarction
● May have abdominal discomfort, pain, anorexia or fatigue (Hepatobiliary Pancreat Dis Int. 2004;3:199)
● Telangiectatic FNH are monoclonal and more closely resemble hepatic adenomas than classical FNH


● May represent hyperplastic response to preexisting arterial malformation or other vascular anomaly; is NOT a neoplasm (Am J Gastroenterol 2006;101:2341)

Diagram of possible pathogenesis

Case reports

● 13 month old girl (Case of the Week #88)

Radiology decription

● Mass with central scar, centrifugal hypervascularity by angiography
● CT and MRI are important, but often cannot make a definite preoperative diagnosis (Hepatobiliary Pancreat Dis Int 2007;6:52)


● Excellent prognosis
● Adult women should discontinue oral contraceptives, if applicable
● Surgery if symptomatic, complications, compression of adjacent organs or lesion progression (Eur J Pediatr Surg 2006;16:235)

Gross description

● Well demarcated, nonencapsulated, subcapsular, light brown to yellow (lighter than surrounding liver)
● Bulging nodule, 70-80% solitary, up to 5 cm; rarely > 10 cm
● Central gray-white stellate scar (unless < 1 cm) from which fibrous septa radiate to periphery and create multiple smaller nodules
● Hemorrhage, necrosis, infarction, bile staining often seen; larger tumors may have multiple scars; adjacent liver is normal

Gross images

Well circumscribed mass with central stellate scar

Asymptomatic left lobe liver mass

Micro description

● Most tumors (80%) have 3 classic features: abnormal architecture, bile ductular proliferation, malformed vessels
● Hepatocyte nodules are surrounded by fibrous septa with large malformed arterial branches not accompanied by interlobular bile ducts or portal veins
● Typically void of any formal portal triads
● Septal margins have foci of intense lymphocytic infiltrates and marked bile duct proliferation with histologic changes of chronic cholestasis (Mallory’s hyaline, bile pigment, copper deposits, pseudoxanthomatous change), variable neutrophilic infiltration
● Ductules appear to arise from limiting plate; central scar contains central fibrous body with tortuous large vessels with fibromuscular hyperplasia and luminal narrowing
● Hepatic plates are 1-2 cells thick, similar to surrounding liver, but may be larger and paler with fat or glycogen
● No atypia, no mitotic figures
● Non-classic forms lack either abnormal architecture or malformed vessels, and are devoid of central scar
● 3 types: (a) telangiectatic, (b) mixed hyperplastic and adenomatous, (c) atypia of large cell (Am J Surg Pathol 1999;23:1441)
● Telangiectatic variant: multiple dilated vascular channels in center of mass; considered by some to be a variant of hepatic adenoma (World J Gastroenterol 2007;13:2649)
● Mixed hyperplastic and adenomatous: contain regions resembling telangiectatic and hepatic adenoma
● Atypia of large cell: atypical hepatocytes with enlarged hyperchromatic nuclei with irregular contours frequently demonstrating cytoplasmic–nuclear inclusions

Micro images

Fibrous area with blood vessels and bile ductules

Associated with fibrolamellar carcinoma

Asymptomatic left lobe liver mass

Positive stains

● Alpha-1-antitrypsin

Negative stains

● p53, CD143 (angiotensin I-converting enzyme: reduced expression, Am J Surg Pathol 2004;28:84)

Differential diagnosis

● Osler-Weber-Rendu disease, Budd-Chiari syndrome or cirrhosis (adjacent liver is not normal), fibrolamellar hepatocellular carcinoma (marked atypia of hepatocytes), hepatocellular adenoma (encapsulated, monoclonal), peritumoral hyperplasia (Arch Pathol Lab Med 2000;124:1105)

Additional references

Radiographics 2004;24:3, eMedicine

Multiple focal nodular hyperplasia syndrome


● Multiple FNH lesions plus one other lesion: either hepatic hemangioma, arterial dysplasia, Klippel-Trenaunay-Weber syndrome, Turner's syndrome, brain telangiectasia, berry aneurysm, astrocytoma or meningioma

Micro description

● Often telangiectatic variant with multiple dilated vascular channels in center of mass

End of Liver and intrahepatic bile ducts - Tumor > Benign tumors > Focal nodular hyperplasia (FNH)

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