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Year : 2020  |  Volume : 63  |  Issue : 3  |  Page : 441-444
Inflammatory myofibroblastic tumor manifesting as recurrent generalized gingival enlargement: Report of a rare case

1 Division of Periodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India
2 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
3 Department of Prosthodontics, Surendera Dental College and Research Institute, Sriganganagar, Rajasthan, India
4 Division of Pedodontics and Preventive Dentistry, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India

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Date of Submission31-May-2019
Date of Decision04-Aug-2019
Date of Acceptance06-Aug-2019
Date of Web Publication7-Aug-2020


Oral inflammatory myofibroblastic tumor (IMT) is extremely rare and its manifestation as generalized gingival enlargement (GGE) has never been reported. We are reporting the case of 50-year-old female patient presenting with recurrent GGE for 4 years. Panoramic radiograph revealed severe bone loss in posterior sextants and root resorption in some teeth. Initial incisional biopsy was suggestive of chronic inflammatory infiltrate with fibrocollagenous tissue. Definitive treatment comprised of surgical excision of the enlarged gingiva with a tapering dose of steroid therapy. Histopathological and immunohistochemical examination from a repeat biopsy of deeper tissues was suggestive IMT. No recurrence was found at 2 years follow up. Recurrent GGE with advanced bone loss and external root resorption should raise the suspicion of a locally aggressive lesion. Dentists should be aware of oral IMT and include it in differential diagnosis of gingival enlargements for comprehensive management to avoid recurrence of the lesion.

Keywords: ALK positive, gingival enlargement, inflammatory myofibroblastic tumor, Ki67, smooth muscle actin

How to cite this article:
Yadav VS, Das P, Yadav R, Tewari N. Inflammatory myofibroblastic tumor manifesting as recurrent generalized gingival enlargement: Report of a rare case. Indian J Pathol Microbiol 2020;63:441-4

How to cite this URL:
Yadav VS, Das P, Yadav R, Tewari N. Inflammatory myofibroblastic tumor manifesting as recurrent generalized gingival enlargement: Report of a rare case. Indian J Pathol Microbiol [serial online] 2020 [cited 2022 Jan 18];63:441-4. Available from: https://www.ijpmonline.org/text.asp?2020/63/3/441/291670

   Introduction Top

World Health organization (WHO) defined inflammatory myofibroblastic tumor (IMT) as an intermediate soft tissue tumor composed of myofibroblast differentiated spindle cells and accompanied by numerous inflammatory cells, plasma cells, and/or lymphocytes.[1]

Although lungs are most commonly involved site, head and neck region comprises 14-18% of extrapulmonary sites of IMT.[2] It shows a high predilection for children and young adults; however, it has been reported in all age groups.[1] Oral IMTs are extremely rare and have been reported to involve buccal mucosa, jaw bones, tongue, extraction sites, hard palate, floor of the mouth, and retromolar area.[3],[4],[5] Gingiva is one of the rarest site for IMT and only reported as isolated lesions.[5],[6],[7]

To the best of our knowledge, this unique case report describes the first and extremely rare presentation of oral IMT manifesting as generalized gingival enlargement in a middle-aged female patient.

   Case Report Top

A 50-year old afebrile female patient of average height and weight presented with a nonpainful, recurrent, generalized gum swelling with gradual onset in both jaws since 4 years. She reported occasional bleeding from the gums, bad breath, difficulty in chewing and loose/missing teeth. The medical, drug, and family history were noncontributory. Biopsy results from previous surgeries were also inconclusive.

Extraoral examination exhibited mild asymmetry of the face with bilateral fullness without any lymphadenopathy. Intraoral examination exhibited generalized gingival enlargement which was relatively more pronounced in the molar regions [Figure 1]a. It was firm in consistency, nontender on palpation and pale pink in color with generalized loss of stippling. Grade III mobility with malpositioning was seen in teeth 36,37,38,48,16,17,18 and Grade II mobility in15,24,45. Gingival enlargement in posterior areas was flabby and loosely attached indicating an advanced bone loss.
Figure 1: Preoperative photographs (a) generalized gingival enlargement in frontal view and (b) Panormic radiograph showing severe bone loss in posterior sextants and root resorption

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Orthopantomogram revealed generalized bone loss and presence of all permanent teeth except 25,26,27,28,46,47. Severe alveolar bone resorption was noted in molar areas of both the arches along with external root resorption in 36,37,16,17 [Figure 1]b. Hematological and biochemical investigations were within normal limits. Chest radiographs disclosed no occult disease.

After written and informed consent, scaling, and root planing was performed with hand and ultrasonic instruments at initial visit. Oral anti-inflammatory drugs along with 0.2% chlorhexidine digluconate mouthrinse were prescribed. After a follow-up of 2 weeks, there was no decrease in the size of enlarged gingiva. An incisional biopsy of the gingiva was suggestive of mild chronic inflammatory infiltrate with fibrocollagenous tissue. Definitive treatment plan comprised of surgical excision of the enlarged gingiva in posterior sextants of 1st, 3rd, and 4th quadrant along with removal of grade III mobile teeth under local anesthesia. Transgingival probing revealed the bony overgrowths on the labial aspects of the maxillary anterior region which was subsequently confirmed with the surgical exposure. Internal bevel gingivectomy was performed in the anterior sextants without any osseous resection. The excised tissue was sent for histopathological examination.

Histopathologic examination revealed ulceration of the surface stratified squamous epithelium and underlying chronic inflammatory granulation tissue [Figure 2]a and [Figure 2]b. In deeper part of the tissue fragments, a benign fibroblastic lesion with interspersed medium sized blood vessels and moderately dense lymphoplasmacytic cell infiltrate was observed [Figure 2]c. Occasional scattered eosinophils were also identified. However, significant nuclear pleomorphism and atypical mitotic figures were not present. Definite storiform arrangement or obliterative phlebitis was not identified.
Figure 2: Histologic sections shows (a) subepithelial fibroblastic lesion infiltrated with chronic inflammatory cells [hematoxyline and eosin stain; magnification ×40] (b) Submucosal plasmacytosis [hematoxyline and eosin stain; magnification ×100]. (c) Benign fibroblasts admixed with lymphocytes, plasma cells and eosinophils [hematoxyline and eosin stain; magnification ×200]

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Immunohistochemical analysis was performed by the biotin-streptavidin-peroxidase method. The spindle cells showed focal positivity for smooth muscle actin (SMA) [Figure 3]a, CD34 [Figure 3]b, and ALK-1 [Figure 3]c immunohistochemical stains. Ki67 labeling index was around 1% in the highest proliferation zone [Figure 3]d. Immunostain for IgG4 stain was negative.
Figure 3: Immunohistochemical stains shows (a) positivity of the spindle cells for smooth muscle actin [magnification x200], (b) CD34 [magnification x100] and (c) ALK-1 stains [magnification x200]. (d) Ki67 labeling index was around 1% [magnification x200]

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Based on the histopathological and immunohistochemical findings, a diagnosis of IMT was made. Medical treatment in the form of oral steroids i.e., prednisolone at a dose 1 mg/kg/day was started after establishment of final diagnosis of IMT and continued for 1 month. Dose was then tapered gradually (5–10 mg decrements every 1 week until a physiological dose of 5 mg/day) followed by withdrawal of steroid therapy.

No recurrence of enlargement was observed at 2 years follow-up visit [Figure 4]a. A repeat panoramic radiograph displayed some osseous regeneration at the previous sites of resorption [Figure 4]b.
Figure 4: Postoperative photographs (a) after 1 year follow up showing no recurrence of gingival enlargement (b) Panoramic radiograph at 2 years showing some osseous regeneration at the previous sites of resorption

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   Discussion Top

Oral IMT is an exceedingly rare lesion of nonspecific clinical and radiographic presentation. Perusal of the available literature did not reveal any reported case of intraoral IMT manifesting as generalized gingival enlargement, thereby rendering this report to be first of its kind.

Clinical differential diagnosis of drug-induced gingival enlargement was ruled out as patient was systemically healthy and not on any medication. Inflammatory etiology was excluded as the enlargement was nonresponsive to anti-inflammatory drugs with initial periodontal therapy. A possibility of an IgG4-related sclerosing disease was also ruled out.

It is quite common for patients with IMT to undergo multiple biopsy procedures to establish a diagnosis as was also seen in present case. It is advisable to take the biopsy from deeper parts of the lesion especially when predominated peripherally by inflammatory cells to avoid misdiagnosis.[2] The histological differential diagnosis of IMT includes benign and malignant spindle cell lesions [Table 1].[4] Among the different histological patterns described by WHO,[1] present case exhibited a compact spindle cell pattern.
Table 1: Histological differential diagnosis of IMT

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The exact etiopathogenesis of IMT is not known. It is considered possibly an extravagant immune response to certain viral agents (Epstein-Barr virus, cytomegalovirus, human herpes virus-8), surgery, trauma, adjacent necrotic tissue, foreign body or radiotherapy.[8],[9],[10] No viral infection was detected in our case and previous history was also noncontributory. The ALK gene on chromosome band 2p23 is thought to be involved in the pathogenesis of IMT.[11] Most of the previously reported oral IMTs were ALK negative.[6] The present case was however positive for ALK immunoexpression.

About 0–10% of IMTs exhibit the presence of the nuclear protein Ki-67 which is usually associated with underlying neoplastic process and is a measure of the ongoing proliferative activity.[5] Nuclear immunopositivity for Ki-67 was demonstrated in <1% of the tumor cells in the present case.

Treatment of IMT comprises surgical excision, curettage, corticosteroid therapy, radical surgery, radiotherapy, chemotherapy, and a combination of one of these modalities.[4] Compete surgical excision with free margins remains the mainstay of IMT treatment. Radiotherapy and/or chemotherapy (ALK inhibitors) have been employed for the treatment of lesions showing neoplastic and aggressive behavior.[4],[12] Based on the findings of the available literature, it has been proposed that high dose systemic corticosteroids can be employed if complete surgical excision is impossible or unsuccessful particularly in relatively nonaggressive, non-neoplastic lesions.[4],[13],[14] Due to generalized and diffuse gingival involvement, it was difficult to determine the margins of the lesion to ensure complete excision in present case. Therefore, patient was given a course of steroids along with the surgical excision of enlarged gingiva.

Oral IMTs usually run a more favorable clinical course and respond well to the treatment with no reported recurrence.[3],[5] However, in the present case, patient underwent surgical excision of the enlarged gingiva three times but there was recurrence within 3 months of surgery. It may be attributed to the lack of correct diagnosis of the lesion and subsequent treatment. Ki67 expression and ALK positive nature of the lesion may also have contributed to the recurrence in absence of wide surgical excision.

The cause of external root resorption in the present case is poorly understood and has never been reported except from a case of intrabony IMT.[15] It may be hypothesized that the pressure from gradual increase in size of the gingival IMT, depicting a locally aggressive behavior, might have caused the root resorption, pathological migration, and associated tooth mobility.

   Conclusion Top

Oral IMT is a rare locally aggressive lesion with nonspecific clinical, radiographic, and pathological features. Dentists should be aware of oral IMT and its comprehensive management in order to avoid recurrence of the lesion.

Declaration of patient consent

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

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Coffin CM, Fletcher JA. Inflammatory myofibroblastic tumour. In: Fletcher CDM, Bridge JA, Hogendoorn PCW, Mertens F, editors. World Health Organization Classification of Tumours Soft Tissue and Bone. Lyon: IARC Press; 2013. p. 83-4.  Back to cited text no. 1
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. 2
Brooks JK, Nikitakis NG, Frankel BF, Papadimitriou JC, Sauk JJ. Oral inflammatory myofibroblastic tumor demonstrating ALK, p53, MDM2, CDK4, pRb, and Ki-67 immunoreactivity in an elderly patient. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:716-26.  Back to cited text no. 3
Devaney KO, Lafeir DJ, Triantafyllou A, Mendenhall WM, Woolgar JA, Rinaldo A, et al. Inflammatory myofibroblastic tumors of the head and neck: Evaluation of clinicopathologic and prognostic features. Eur Arch Otorhinolaryngol 2012;269:2461-5.  Back to cited text no. 4
Binmadi NO, Packman H, Papadimitriou JC, Scheper M. Oral inflammatory myofibroblastic tumor: Case report and review of literature. Open Dent J 2011;5:66-70.  Back to cited text no. 5
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. 6
Naresh N, Malik A, Jeyaraj P, Haranal S. Inflammatory myofibroblastic tumor of the oral cavity. A great mimicker. N Y State Dent J 2015;81:34-6.  Back to cited text no. 7
Eley KA, Watt-Smith SR. Intraoral presentation of inflammatory myofibroblastic tumor (pseudotumor) at the site of dental extraction: Report of a case and review of the literature. J Oral Maxillofac Surg 2010;68:2016-20.  Back to cited text no. 8
Kim SY, Yang SE. Inflammatory myofibroblastic tumor of the maxillary sinus related with pulp necrosis of maxillary teeth: Case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:684-7.  Back to cited text no. 9
Oota S, Shibuya H, Hamagaki M, Yoshimura R, Iwaki H, Kozima M, et al. Oral pseudotumor: Benign polypoid masses following radiation therapy. Cancer 2003;97:1353-7.  Back to cited text no. 10
Coffin CM, Patel A, Perkins S, Elenitoba-Johnson KSJ, Perlman E, Griffin CA. ALK1 and p80 expression and chromosomal rearrangements involving 2p23 in inflammatory myofibroblastic tumor. Mod Pathol 2001;14:569-76.  Back to cited text no. 11
Butrynski JE, D'Adamo DR, Hornick JL, Dal Cin P, Antonescu CR, Jhanwar SC, et al. Crizotinib in ALK-rearranged inflammatory myofibroblastic tumor. N Engl J Med 2010;363:1727-33.  Back to cited text no. 12
Lazaridou M, Dimitrakopoulos I, Tilaveridis I, Iordanidis F, Kontos K. Inflammatory myofibroblastic tumour of the maxillary sinus and the oral cavity. Oral Maxillofac Surg 2014;18:111-4.  Back to cited text no. 13
Adachi M, Kiho K, Sekine G, Ohta T, Matsubara M, Yoshida T, et al. Inflammatory myofibroblastic tumor mimicking apical periodontitis. J Endod 2015;41:2079-82.  Back to cited text no. 14
Rautava J, Soukka T, Peltonen E, Nurmenniemi P, Kallajoki M, Syrjänen S. Unusual case of inflammatory myofibroblastictumor in maxilla. Case Rep Dent 2013;2013:876503.  Back to cited text no. 15

Correspondence Address:
Vikender S Yadav
Division of Periodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi - 110 029
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_431_19

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