Inflammatory myofibroblastic tumour of the lung

Inflammatory myofibroblastic tumours of the lungs are a location specific type of inflammatory myofibroblastic tumours.

They are very rare with their incidence reported at approximately 0.04-1% of all the pulmonary neoplasms 1. While it can affect any age group, around 25% of cases occur in whose under 18 yeas of age.

It is generally considered to fall within the benign spectrum of tumours.

Microscopically they are characterised by abundant inflammatory infiltrate comprising of predominantly plasma cells, lymphocytes, histiocytes, admixed with a variable proportion of fibroblasts and myofibroblasts.

On immunohistochemistry, the tumour cells can exhibit

  • strong diffuse positivity with smooth muscle actin and vimentin
  • negativity for cytokeratin, CD34 and S100
Subtypes

They are sometimes divided into two subtypes:

  • non-invasive
  • invasive: usually occurs among younger patients and may reach large sizes
CT

Typically seen as a single (can be multiple around in 5% of cases) peripheral, lobulated mass with lower lobe predominant occurrence. Calcification can occur (commoner in tumours occurring in children). Usually shows heterogeneous enhancement with contrast.

Nuclear medicine

Usually avid on FDG PET-CT.

It behaviour if often variable and the overall prognosis is often dependent on tumour size 3. Radical resection with negative margins is often the mainstay of treatment while radiation and steroids may be options in those who cannot undergo surgery. Long-term surveillance is often recommended due to local and distant recurrence as well as possible of sarcomatous degeneration. 

They were was first observed in lungs and described by Bunn in 1939 2.

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Article information

rID: 43148
System: Chest
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Inflammatory myofibroblastic tumour of lungs
  • Inflammatory myofibroblastic tumour of the lungs
  • Inflammatory myofibroblastic tumours of the lung
  • Inflammatory myofibroblastic tumours of the lungs
  • Inflammatory myofibroblastic tumors of the lung
  • Inflammatory myofibroblastic tumors of the lungs
  • Inflammatory myofibroblastic tumor of lung
  • Plasma cell granuloma of lung
  • Plasma cell granuloma of lungs
  • Plasma cell granuloma of the lung

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