Liver & intrahepatic bile ducts
Benign / nonneoplastic
Inflammatory myofibroblastic tumor

Topic Completed: 1 February 2012

Minor changes: 1 August 2020

Revised: 25 January 2019, last major update February 2012

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

PubMed Search: Inflammatory myofibroblastic tumor[TI] liver[TIAB]

Deepali Jain, M.D.
Page views in 2019: 1,043
Page views in 2020 to date: 736
Cite this page: Jain D. Inflammatory myofibroblastic tumor. website. Accessed August 14th, 2020.
Definition / general
  • Uncommon lesion
  • ALK1+: neoplastic lesion with intermediate biologic behavior
  • ALK1-: considered reactive
  • Also called inflammatory pseudotumor
  • In extrapulmonary tumors, recurs locally in 25%; 8% metastasize
  • Usually children and young adults; mean age 37 years but all ages, 75% male
  • Associated with occlusive phlebitis and chronic cholangitis
  • Rarely associated with sarcoma or follicular dendritic cell tumor
  • Symptoms: fever, upper abdominal pain, jaundice
  • Excision, occasionally regresses spontaneously
Gross description
  • Well circumscribed, solitary (70%), 1 - 25 cm, variegated cut surface, may extend into vena cava or soft tissue, predominantly right lobe
Microscopic (histologic) description
  • Plasma cells, lymphocytes, neutrophils, macrophages, mast cells and myofibroblast-like spindled cells in varying amounts, in whorled, fibrotic stroma
  • Occasional myxoid areas, minimal vascular component; minimal pleomorphism, no / rare mitotic activity
  • Rarely is highly cellular or has mitotic activity (often in children)
  • Aggressive morphologic features: p53+, ganglion-like cells, mitotic figures (Mod Pathol 1999;12:279); also epithelioid and round cell morphology, nuclear membrane staining of ALK (in contrast to diffuse cytoplasmic staining in benign, Am J Surg Pathol 2011;35:135)
Positive stains
Negative stains
Differential diagnosis
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