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
They are sometimes divided into two subtypes:
- invasive: usually occurs among younger patients and may reach large sizes
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.
Usually avid on FDG PET-CT.
Treatment and prognosis
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.
History and etymology
They were was first observed in lungs and described by Bunn in 1939 2.
- 1. Pavithran K, Manoj P, Vidhyadharan G et-al. Inflammatory myofibroblastic tumor of the lung: unusual imaging findings. World J Nucl Med. 2013;12 (3): 126-8. doi:10.4103/1450-1147.136739 - Free text at pubmed - Pubmed citation
- 2. van den Heuvel DA, Keijsers RG, van Es HW et-al. Invasive inflammatory myofibroblastic tumor of the lung. J Thorac Oncol. 2009;4 (7): 923-6. doi:10.1097/JTO.0b013e3181a76e28 - Pubmed citation
- 3. Chen CK, Jan CI, Tsai JS et-al. Inflammatory myofibroblastic tumor of the lung-a case report. J Cardiothorac Surg. 2010;5 (1): 55. doi:10.1186/1749-8090-5-55 - Free text at pubmed - Pubmed citation
- 4. Lee HJ, Kim JS, Choi YS et-al. Treatment of inflammatory myofibroblastic tumor of the chest: the extent of resection. Ann. Thorac. Surg. 2007;84 (1): 221-4. doi:10.1016/j.athoracsur.2007.03.037 - Pubmed citation
- 5. Sakurai H, Hasegawa T, Watanabe Si et-al. Inflammatory myofibroblastic tumor of the lung. Eur J Cardiothorac Surg. 2004;25 (2): 155-9. Pubmed citation
- 6. Firat O, Ozturk S, Akalin T et-al. Inflammatory myofibroblastic tumour. Can J Surg. 2009;52 (3): E60-1. Free text at pubmed - Pubmed citation