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Table of Contents    
Year : 2020  |  Volume : 68  |  Issue : 3  |  Page : 703-705

Central Nervous System Inflammatory Myofibroblastic Tumor Presenting as a Scalp Abscess

1 Department of Neurosurgery, Government Medical College, Thrissur, Kerala, India
2 Department of Pathology, Government Medical College, Thrissur, Kerala, India

Date of Web Publication6-Jul-2020

Correspondence Address:
Dr. Binoy D Thavara
Department of Neurosurgery, Government Medical College, Thrissur - 680 596, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.289026

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How to cite this article:
Thavara BD, Rajagopalawarrier B, Ramaswamy JC, Kidangan GS. Central Nervous System Inflammatory Myofibroblastic Tumor Presenting as a Scalp Abscess. Neurol India 2020;68:703-5

How to cite this URL:
Thavara BD, Rajagopalawarrier B, Ramaswamy JC, Kidangan GS. Central Nervous System Inflammatory Myofibroblastic Tumor Presenting as a Scalp Abscess. Neurol India [serial online] 2020 [cited 2021 Jul 26];68:703-5. Available from:


The Inflammatory Myofibroblastic tumor (IMT) is a heterogeneous group of rare lesions consisting predominantly of inflammatory cells and myofibroblastic spindle cells.[1] Central nervous system inflammatory myofibroblastic tumor (CNS IMT) is rare, with only approximately 100 cases reported in the literature. The etiology is unknown, but 60% have arisen from the dural or meningeal structures, and only 12% from intraparenchymal structures.[2] An aberrant or exaggerated response to tissue injury without an established cause has been favoured as the pathogenesis of IMT.[3]

A 47-year-old male patient presented with a pus discharging sinus from left parietal region. One year ago, he had noticed a gradually increasing scalp swelling. It was treated as a scalp abscess with incision and drainage. In the following months, he had noticed headache and intermittent minimal pus discharge from the incision site. In 2012, there was a history of head injury with right frontal sinus fracture. On examination, a 10 × 10 cm rounded prominence of the left parietal scalp with central scar and pus discharging sinus was noted [Figure 1]. Computed tomography (CT) scan and Magnetic resonance imaging (MRI) scan showed a 4.5 × 4 × 2.4 cm extra axial broad dural based left parietal lesion which has eroded the overlying bone and infiltrated into the scalp. T1 contrast image showed homogenous intense contrast enhancement of the tumor and its surrounding dura [Figure 2] and [Figure 3]a, [Figure 3]b, [Figure 3]c. There was no evidence of superior sagittal sinus thrombosis. Another 1.3 cm contrast enhancing nodular lesion was noted in the right parietal diploic space causing defect in the outer table. A provisional diagnosis of the intradiploic meningioma was made [Figure 3]a. Serum electrophoresis and Prostate Specific Antigen were normal. Chest X-ray and Ultrasound of the abdomen were normal.
Figure 1: Rounded scar in the scalp with pus discharging central sinus was noted

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Figure 2: Contrast enhanced CT scan coronal image showing intense homogenous contrast enhancing extra axial lesion which has eroded the parietal bone and extended into the scalp

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Figure 3: Axial (a), sagittal (b) and coronal (c) T1 contrast image showing intense contrast enhancing extra axial lesion arising from the convexity and parasagittal dura with surrounding dural enhancement. The lesion has eroded the left parietal bone and extended into the scalp. The image also shows a small intense contrast enhancing lesion in the right parietal bone in the diploic space causing defect in the outer table

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At surgery, the tumor was arising from the convexity and parasagittal dura. It has eroded through the parietal bone and infiltrated into the scalp [Figure 4]a and [Figure 4]b. It was a greyish-red moderately vascular tumor with firm to hard in consistency. Tumor capsule was noted. There was no macroscopic infiltration into the brain parenchyma. The tumor was excised along with 3 cm of surrounding dura. The dural defect was covered with polypropylene patch. Histopathological examination showed a neoplasm composed of spindle cells arranged in vague storiform pattern. Background showed dense inflammatory infiltrates of plasma cells, lymphocytes, eosinophils, and neutrophils [Figure 5]a. Immunohistochemistry (IHC) examination showed myofibroblastic spindle cells which were Smooth Muscle Actin (SMA) positive [Figure 5]b and Anaplastic Lymphoma Kinase (ALK) negative [Figure 5]c. Hence diagnosis of CNS IMT was made.
Figure 4: (a) Tumor erosion through the parietal bone noted. (b) Tumor has infiltrated through the dura and spread extradurally

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Figure 5: (a) High power microscopy of the tumor showing a neoplasm composed of spindle cells. Background showed dense inflammatory infiltrate composed of plasma cells, lymphocytes, eosinophils, and neutrophils. (b) IHC showing myofibroblastic spindle cells which are SMA positive. (c) IHC showing ALK negative cells. (IHC – Immunohistochemistry, SMA - Smooth Muscle Actin, ALK - Anaplastic Lymphoma Kinase)

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In WHO classification of CNS tumors (2016), IMT is classified as mesenchymal, non-meningothelial tumors. The behaviour of IMT is described as unspecified, borderline or uncertain behaviour.[4] It is a benign, non-metastasizing proliferation of myofibroblasts with a potential for recurrence and persistent local growth.[5] Radical resection and obtaining negative margins remain the mainstay of treatment.[6] The recurrence rate after gross total resection for ALK-positive and ALK-negative cases was 33% and 9%, respectively.[7] Hausler M et al., reported a case of left occipital IMT. After resection, patient developed a rapidly progressive local recurrence and a second intracerebral lesion.[2] In the author's case, patient has another small lesion in the right parietal intradiploic space, the pathology of which is not known. Localized or diffuse dural thickening of T2 low signal intensity and diffuse contrast enhancement combined with dural-based masses are a common MRI finding of meningeal intracranial IMT. Adjacent leptomeningeal involvement and dural venous sinus thrombosis are frequently associated.[8]

To conclude, the authors report the first case of locally aggressive CNS IMT, which has eroded through the skull bone and presented as a scalp abscess.[9] Trauma can be considered as one of the inciting agents for the development of CNS IMT. In every suspicious scalp swelling, intracranial extension should be ruled out before proceeding with surgery. Radiological diagnosis of CNS IMT is difficult in view of radiologically mimicking common tumors. The definitive diagnosis is done by using histology and IHC. The aggressiveness of the tumor is not well known in view of rarity of the tumor.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that name and initial will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Satomi T, Watanabe M, Matsubayashi J, Nagao T, Chiba H. A successfully treated inflammatory myofibroblastic tumor of the mandible with long-term follow-up and review of the literature. Med Mol Morphol 2010;43:185-91.  Back to cited text no. 1
Häusler M, Schaade L, Ramaekers VT, Doenges M, Heimann G, Sellhaus B. Inflammatory pseudotumors of the central nervous system: Report of 3 cases and a literature review. Human Pathol 2003;34:253-62.  Back to cited text no. 2
Coffin CM, Dehner LP, Meis-Kindblom JM. Inflammatory myofibroblastic tumor, inflammatory fibrosarcoma, and related lesions: An historical review with differential diagnostic considerations. Semin Diagn Pathol 1998;15:102-10.  Back to cited text no. 3
Louis DN, Perry A, Reifenberger G, von Deimling A, Figarella-Branger D, Cavenee WK, et al. The 2016 world health organization classification of tumors of the central nervous system: A summary. Acta Neuropathol 2016;131:803-20.  Back to cited text no. 4
Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor). A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol 1995;19:859-72.  Back to cited text no. 5
Ong HS, Ji T, Zhang CP, Li J, Wang LZ, Li RR, et al. Head and neck inflammatory myofibroblastic tumor (IMT): Evaluation of clinicopathologic and prognostic features. Oral Oncol 2012;48:141-8.  Back to cited text no. 6
Denis DJ, Elayoubi K, Weil AG, Berthelet F, Bojanowski MW. Inflammatory myofibroblastic tumors of the central nervous system that express anaplastic lymphoma kinase have a high recurrence rate. Surg Neurol Int 2013;4:70.  Back to cited text no. 7
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Kim JH, Chang KH, Na DG, Park SH, Kim E, Han DH, et al. Imaging features of meningeal inflammatory myofibroblastic tumor. Am J Neuroradiol 2009;30:1261-7.  Back to cited text no. 8
Mankotia DS, Garg K, Nambirajan A, Suri V, Tandon V, Kumar R, et al. Primary Spinal extradural inflammatory myofibroblastic tumor: A rare cause of paraparesis. Neurol India. 2016;64:1333-5.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]


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