Liver and intrahepatic bile ducts - tumor
Benign tumors / conditions
Focal nodular hyperplasia (FNH)

Author: Deepali Jain, M.D. (see Authors page)

Revised: 16 November 2017, last major update February 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Focal nodular hyperplasia[TI] liver[TI] free full text[sb]

Cite this page: Jain, D. Focal nodular hyperplasia (FNH). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/livertumorFNH.html. Accessed January 21st, 2018.
Definition / general
  • 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
  • Multiple focal nodular hyperplasia syndrome: multiple FNH lesions plus one other lesion - either hepatic hemangioma, arterial dysplasia, Klippel-Trenaunay-Weber syndrome, Turner syndrome, brain telangiectasia, berry aneurysm, astrocytoma or meningioma
Etiology
Diagrams / tables

Images hosted on other servers:

Diagram of possible pathogenesis

Radiology description
Case reports
Treatment
  • 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

Images hosted on PathOut server:

Images contributed by Dr. Hanni Gulwani, Sir Ganga Ram Hospital, New Delhi (India):

Well circumscribed mass with central stellate scar



Images hosted on other servers:

Images contributed by Dr. Mohammed Sami Saaed, University of Mosul, Iraq:

Asymptomatic left lobe liver mass

Microscopic (histologic) 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 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
  • Nonclassic forms lack either abnormal architecture or malformed vessels and are devoid of central scar
  • 3 types:
    1. Telangiectatic
    2. Mixed hyperplastic and adenomatous
    3. 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 cytoplasmicnuclear inclusions
  • Multiple focal nodular hyperplasia syndrome: often telangiectatic variant with multiple dilated vascular channels in center of mass
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Dr. Hanni Gulwani, Sir Ganga Ram Hospital, New Delhi (India):

Fibrous area with blood vessels and bile ductules



Images hosted on other servers:

Associated with fibrolamellar carcinoma



Images contributed by Dr. Mohammed Sami Saaed, University of Mosul, Iraq:


Asymptomatic left lobe liver mass

Positive stains
Negative stains
Differential diagnosis