|Year : 2013 | Volume
| Issue : 3 | Page : 229-231
Inflammatory myofibroblastic tumor of the peripheral soft tissue: A case report
Babina Sarangthem, Ph Madhubala Devi, Oinam Okendrajit Singh, Durlav Chandra Sharma
Department of Pathology, Regional Institute of Medical Sciences, Imphal, Manipur, India
|Date of Web Publication||19-Feb-2014|
Department of Pathology Regional Institute of Medical Sciences, Imphal - 795 004, Manipur
Source of Support: None, Conflict of Interest: None
A 52-year-old woman presented with a painless lump at right buttock of 14 years duration with history of sudden increase in size for the last 2 months. Fine needle aspiration cytology (FNAC) examination suggested a fibrohistiocytic lesion. Histopathological examination with subsequent immunohistochemistry diagnosed the case as inflammatory myofibroblastic tumor (IMT) of the peripheral soft tissue. IMT of the peripheral soft tissue especially in older patients are comparatively rare and the case is reported for its rarity.
Keywords: Inflammatory myofibroblastic tumor, Myofibroblast, Smooth muscle actin
|How to cite this article:|
Sarangthem B, Devi P, Singh OO, Sharma DC. Inflammatory myofibroblastic tumor of the peripheral soft tissue: A case report. J Med Soc 2013;27:229-31
|How to cite this URL:|
Sarangthem B, Devi P, Singh OO, Sharma DC. Inflammatory myofibroblastic tumor of the peripheral soft tissue: A case report. J Med Soc [serial online] 2013 [cited 2020 Oct 20];27:229-31. Available from: https://www.jmedsoc.org/text.asp?2013/27/3/229/127402
| Introduction|| |
Inflammatory myofibroblastic tumors (IMT) are clinicopathologically distinctive tumors of disputed pathogenesis.  IMTs usually arise in the soft tissues most often in the abdomen in children and adolescents. These tumors are composed of myofibroblastic spindle cells admixed with a prominent mixed inflammatory cell infiltrate composed of lymphocytes, plasma cells, and sometimes acute inflammatory cells.  Potential for local recurrence and metastasis has been seen in some subsets, so strict follow-up is required after surgery. IMT of the peripheral soft tissue especially in older patients are comparatively rare and the case is reported for its rarity.
| Case Report|| |
A 52-year-old woman presented with a painless lump at the right buttock of 14 years duration. The lump suddenly increased in size for the last 2 months. Local examination revealed a well-defined firm lump measuring (12 × 8 cm), nontender, and freely mobile; but restricted mobility on contraction of muscle. A diagnosis of desmoid tumor was suggested in radiographic (magnetic resonance imaging (MRI)) study. Fine needle aspiration cytology (FNAC) showed benign looking spindle cells, lymphocytes, and plasma cells with fibromyxoid stroma in the background. A diagnosis of fibrohistiocytic lesion was suggested.
On histopathological examination, gross findings revealed a partially capsulated single globular greyish white mass measuring 12 × 8 cm. Cut surface showed partial capsulation with multiple greyish white nodules of variable sizes and foci of hemorrhages [Figure 1]. Microscopic examination showed a cellular tumor composed of fibroblasts and myofibroblastic spindle cells in fascicles with dense and diffuse lymphoplasmacytic infiltration. A few atypical large bizarre myofibroblastic cells, foci of hyalinization, and hemorrhage were also seen [Figure 2] and [Figure 3]. The lesion was diagnosed as IMT. Vimentin and smooth muscle actin were positive on immunohistochemistry study done by horseradish peroxidase method using Flex monoclonal mouse antibody to vimentin and smooth muscle actin (Manufacturer: Dako Denmark A/S) confirming the myofibroblastic nature of the spindle cells. Cytogenetic studies could not be done due to lack of facility in our institute.
|Figure 1: Photomicrograph of histopathological section showing fibroblast, myofibroblastic spindle cells in fascicles with dense lymphoplasmacytic infiltrates (hematoxylin and eosin stain (H and E), ×100)|
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|Figure 2 : Gross photograph: Cut surface showing partial capsulation with greyish white nodules and foci of hemorrhage|
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|Figure 3 : Photomicrograph of histopathological section showing fibroblasts, myofibroblasts, and lymphoplasmacytic infiltrates (H and E, ×400)|
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| Discussion|| |
IMT is a clinicopathologically distinctive but biologically controversial entity that was originally described as a nonneoplastic lesion in the lungs.  It is a relatively rare tumor with a wide spectrum of histopathologic features and commonly present as an incidentally discovered mass.  World Health Organization (WHO) defines IMT as a tumor composed of differentiated myofibroblastic spindle cells, numerous lymphocytes, and plasma cells.  Many designations of this tumor include inflammatory pseudotumor, plasma cell granuloma, and plasma cell pseudosarcoma.  The etiology and pathogenesis of IMT is still unknown. An aberrant or exaggerated response to tissue injury without an established cause has been favored as the pathogenesis of the inflammatory pseudotumor. An immunological pathogenesis has also been considered a possible cause. 
Cytogenetic and molecular studies point to the possibility that some subsets of IMT are in fact true neoplasm.  Clonal rearrangements of the short arm of chromosome 2 involving anaplastic lymphoma kinase (ALK) receptor tyrosine kinase locus region have been detected in about 50% of soft tissue IMTs.  IMTs in children and young adults might depend on ALK activation, whereas in older adults there may be a different transforming mechanism.  A subset has been found to be associated with infectious agents such as Epstein-Barr virus in splenic and hepatic IMTs. Actinomycosis, nocardia, mycoplasma, and human herpes virus 8 have also been detected in hepatic and pulmonary IMTs.  IMT is a benign nonmetastasizing proliferation of myofibroblasts with potential recurrence and persistent local growth similar to fibromatosis. In most of the cases, IMTs behave as benign lesions but locally invasive.
Recurrent and metastatic forms of abdominal and intestinal IMTs have also been reported. Three main histologic patterns have been described as nodular fascitis-like, fibrous histiocytoma-like and desmoid scar tissue-like.  The combination of cellular atypia, the presence of ganglion-like cells, p53 expression, and DNA aneuploidy may help to identify IMTs having the potential for aggressive behavior with recurrence or malignant transformation. 
IMTs should be differentiated from other soft tissue myofibroblastic tumors like nodular fascitis, desmoid tumor, inflammatory fibrosarcoma, malignant fibrohistiocytoma, and liposarcoma.  IMTs and inflammatory fibrosarcoma may be the two ends of a neoplastic continuum of myofibroblastic proliferation with cellular atypia and aggressive behavior.  This lesions present most frequently in children and young adults (mean age: 9-10 years), rare in middle age and slightly more common in females.  Extrapulmonary IMTs which occur in younger patients (mean age: 9.1 vs 29.2 years) were found to have higher rate of recurrence.  Clinically, it resembles other proliferative spindle cell lesions. Histopathological examination, immunohistochemistry, and cytogenetic analysis are necessary for proper diagnosis and treatment. Potential for local recurrence and metastasis in some subsets requires strict follow-up after radical surgery.
| References|| |
|1.||Gale N, Zidar N, Padboj J, Volavsek M, Luzar B. Inflammatory myofibroblastic tumour of paranasal sinuses with fatal outcome reactive lesion or tumour? J Clin Pathol 2003;56:715-7. |
|2.||Lawrence B, Perez-Atayde A, Hibbard MK, Rubin BP, Dal Cin P, Pinkus JL, et al. TPM3-ALK and TPM4-ALK Oncogenes in inflammatory myofibroblastic tumors. Am J Pathol 2001;157:377-84. |
|3.||Hagenstad CT, Kilpatrick SE, Pettenati MJ, Savage PD. Inflammatory myofibroblastic tumors with bone marrow involvement. A case report and review of the literature. Arch Pathol Lab Med 2003;127:865-7. |
|4.||Coffin CM, Patel A, Perkins S, Elenitoba-Johnson KS, Perlman E, Griffin CA. ALK1 and p80 expression and chromosomal rearrangements involving 2p23 in inflammatory myofibroblastic tumor. Mod Pathol 2001;14:569-76. |
|5.||Behranwala KA, Straker P, Wan A, Fisher C, Thompson JN. Inflammatory myofibroblastic tumour of the gallbladder. World J Surg Oncol 2005;3:24. |
|6.||Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumour (inflammatory Pseudotumour). A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol 1995;19:859-72. |
[Figure 1], [Figure 2], [Figure 3]