Focal nodular hyperplasia

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Focal nodular hyperplasia
Diagnosis in short

Focal nodular hyperplasia. H&E stain.

LM thick walled blood vessels without bile ducts of same size, bile ductular proliferation at the edge of the fibrosis tissue
LM DDx hepatic adenoma, cirrhosis
Gross well circumscribed with capsule, lighter than surrounding parenchyma - may be yellow, +/-stellate central scar with thick vessels
Site liver - see medical liver disease

Syndromes hereditary hemorrhagic telangiectasia

Radiology usu. solitary lesion, arterial phase enhancement in triphasic imaging
Prognosis benign

Focal nodular hyperplasia, abbreviated FNH, is a benign liver lesion, uncommonly seen by pathologists.

General

Note:

  • Oral contraceptive pill (OCP) use does not appear to be a factor in the growth of these lesions;[3] however, the study claims there is nothing on hepatocellular adenomas -- yet I found a JAMA paper by Rooks et al.[4] on this topic.

Imaging

  • FNH enhances on the arterial phase in triphasic imaging, i.e. triphasic CT or MRI.[5][1]

Gross

Features:[6]

  • Well circumscribed, but no capsule.
  • Lighter than surrounding parenchyma, may be yellow.
  • +/-Stellate central scar with thick vessels.
    • Can be identified on medical imaging.

Note: Usually a solitary lesion.[5]

Microscopic

Features:[6]

  • Classically a stellate scar that has large arteries with fibromuscular hyperplasia.
    • Thin fibrous septa radiate from the central scar - surrounded by lymphocytes & bile ductules.
      • Normal hepatocytes between fibrous septae.

Practical features:

  1. Thick walled blood vessels.
    • Bile duct of same size not seen.
  2. Bile ductular proliferation at the edge of the fibrosis tissue.
  3. Clinical history: it is a focal lesion.

DDx:

  • Hepatic adenoma - may be difficult to distinguish, if no scar and no ductal proliferation.[7]
  • Cirrhosis - complete nodules
    • FNH has incomplete nodules.

Memory device FNH = focal lesion, numerous bile ductules, hyperplasia of arteries.

Images

www:

Trichrome shows fibrous scar with vessels/bile ductules (40X)PAS-D shows tortuous bile ductules at edge of scar with minimal inflammation (200X)PAS-D shows proliferated blood vessels in center of scar with minimal inflammation (200X).Reticulin shows regeneration [two nuclei thick cords between black lines] (400X)

Focal nodular hyperplasia. Trichrome shows fibrous scar with vessels/bile ductules (UL 40X). PAS-D shows tortuous bile ductules at edge of scar with minimal inflammation (UR 200X). PAS-D shows proliferated blood vessels in center of scar with minimal inflammation (LL 200X). Reticulin shows regeneration [two nuclei thick cords between black lines] (LR 400X).

See also

References

  1. 1.0 1.1 Brancatelli, G.; Federle, MP.; Grazioli, L.; Blachar, A.; Peterson, MS.; Thaete, L. (Apr 2001). "Focal nodular hyperplasia: CT findings with emphasis on multiphasic helical CT in 78 patients.". Radiology 219 (1): 61-8. PMID 11274535.
  2. Khalid SK, Garcia-Tsao G (August 2008). "Hepatic vascular malformations in hereditary hemorrhagic telangiectasia". Semin. Liver Dis. 28 (3): 247–58. doi:10.1055/s-0028-1085093. PMID 18814078.
  3. Kapp, N.; Curtis, KM. (Oct 2009). "Hormonal contraceptive use among women with liver tumors: a systematic review.". Contraception 80 (4): 387-90. doi:10.1016/j.contraception.2009.01.021. PMID 19751862.
  4. Rooks, JB.; Ory, HW.; Ishak, KG.; Strauss, LT.; Greenspan, JR.; Hill, AP.; Tyler, CW. (Aug 1979). "Epidemiology of hepatocellular adenoma. The role of oral contraceptive use.". JAMA 242 (7): 644-8. PMID 221698.
  5. 5.0 5.1 http://emedicine.medscape.com/article/368377-overview
  6. 6.0 6.1 Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 922. ISBN 0-7216-0187-1.
  7. STC. 19 Jan 2009.