|Year : 2019 | Volume
| Issue : 3 | Page : 725-728
Inflammatory myofibroblastic tumor of the oral cavity: A case report and literature review
Subraj J Shetty1, Treville Pereira1, Rajiv S Desai2
1 Department of Oral Pathology and Microbiology, School of Dentistry, D. Y. Patil University, Mumbai, Maharashtra, India
2 Department of Oral Pathology and Microbiology, Nair Hospital Dental College, Mumbai, Maharashtra, India
|Date of Web Publication||29-May-2019|
Dr. Subraj J Shetty
Department of Oral Pathology and Microbiology, School of Dentistry, D. Y. Patil University, Sector 7, Nerul, Mumbai - 400 706, Maharashtra
Source of Support: None, Conflict of Interest: None
Inflammatory myofibroblastic tumor (IMT) is a rare tumor of unknown etiology and pathogenesis. The lesion has been recognized to occur at various sites but rarely affects the head and neck region. A 29-year-old male presented with a 13 months' history of a slow growing, painless growth in maxillary left posterior gingiva. An excisional biopsy was performed under local anesthesia. Microscopic examination revealed a compact cellular spindle cell proliferation with collagenous stroma having storiform architecture. Immunohistochemistry revealed that the tumor cells were positive for smooth muscle actin, CD-68 and negative for anaplastic lymphoma kinase. Oral IMT should be included in the differential diagnosis of localized gingival enlargement mimicking oral hyperplastic/reactive lesions.
Keywords: Inflammatory myofibroblastic tumor, myofibroblasts, oral cavity
|How to cite this article:|
Shetty SJ, Pereira T, Desai RS. Inflammatory myofibroblastic tumor of the oral cavity: A case report and literature review. J Can Res Ther 2019;15:725-8
| > Introduction|| |
Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor, primarily occurring in children and young adults. The first case was first observed in the lung and described by Brunn in 1939 and was so named by Umiker et al. in 1954 because its clinical and radiological behavior mimics a malignant process. The most common sites of involvement include the lung, liver, and orbit, but it has been reported to occur in nearly every site of the body, including the major salivary glands and the oral cavity.
Until 1998, it was called inflammatory pseudotumor (IPT), when the term IMT was proposed as being a more descriptive name. The etiology and pathogenesis of IMT remains elusive. Trauma and viral infections such as herpes simplex virus type 8 and Epstein–Barr virus, as well as autoimmune reactions, have been suggested as etiological factors.
Here, we report and describe the clinicopathologic features of a case of IMT arising from the gingiva.
| > Case Report|| |
A 29-year-old male presented with a 13 months' history of a slow growing, painless growth in maxillary left posterior gingiva. The lesion was a well-circumscribed, pedunculated nodule, the same color as the surrounding mucosa, in the area between teeth numbers 26 and 27 [Figure 1]. There was no bleeding or exudates in the area. The patients' medical and social history was noncontributory. Orthopantomogram showed the presence of slight bony erosion in between 26 and 27 [Figure 2]. The initial clinical differential diagnosis was fibroma, peripheral giant cell lesion, pyogenic granuloma, and peripheral ossifying fibroma.
|Figure 1: Intraoral photograph showing a gingival growth in the maxillary left posterior region|
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|Figure 2: Orthopantomogram showing slight bony erosion between maxillary left first and second molar|
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An excisional biopsy was performed under local anesthesia. Gross examination of the specimen revealed a brownish white colored mass, measuring approximately 3 cm × 2.5 cm in size. The cut surface of the lesion was yellowish-white in color and firm in consistency [Figure 3]. Microscopic examination of the soft-tissue specimen, using hematoxylin and eosin stain, revealed a compact cellular spindle cell proliferation with collagenous stroma having storiform architecture. The inflammatory component was minimal with single or small groups of lymphocytes scattered around the spindle cell proliferation [Figure 4]. Immunohistochemistry revealed that the tumor cells were positive for smooth muscle actin [Figure 5], CD-68 [Figure 6], and negative for anaplastic lymphoma kinase (ALK). The final diagnosis was IMT.
|Figure 4: Photomicrograph showing a proliferation of spindle cells admixed with numerous chronic inflammatory cells (H and E, ×40)|
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|Figure 5: Photomicrograph showing immunopositivity for smooth muscle actin (×10)|
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|Figure 6: Photomicrograph showing immunohistochemical expression of CD-68 showing positivity of histiocytes (×10)|
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| > Discussion|| |
Myofibroblasts are ubiquitous cells showing ultrastructural features of both muscle cells and fibroblasts. IMT is a benign neoplasm consisting of variable numbers of inflammatory cells and myofibroblastic spindle cells. Liston et al. in 1981 were the first to report IMTs of oral cavity in three children. The numerous terms used to describe this lesion like pseudosarcomatous myofibroblastic proliferation, inflammatory sarcoma, plasma-cell granuloma, IPT, and inflammatory histiocytic proliferation reflect the initial controversies regarding its etiopathogenesis, histopathology, and nomenclature. Eventually, electron microscopic and immunohistochemical examinations clarified that the proliferating spindle cells in these tumors were myofibroblasts; and therefore, these distinctive tumors are today preferentially called IMTs.
The histologic differential diagnosis of IMT is extensive and includes benign and malignant spindle cell tumors such as nodular fasciitis, solitary fibrous tumor, benign fibrous histiocytoma, calcifying fibrous tumor, myofibroma, fibrosarcoma, follicular dendritic cell tumor, and leiomyosarcoma.
Histologically, IMTs contain a much more prominent inflammatory infiltrate than nodular fasciitis. In addition, they lack the “C-” shaped fascicles and mucin-rich stroma which is responsible for the characteristic “tissue culture-like or feathery” appearance in nodular fasciitis. Solitary fibrous tumor was excluded due to the lack of hemangiopericytoma-like areas and strong CD-34 immunoreactivity.
The diagnosis of benign fibrous histiocytoma was not favored because of the lack of characteristic storiform pattern. Calcifying fibrous tumor, a rare benign neoplasm, is uniformly hypocellular and contains scattered dystrophic calcifications.
The diagnosis of myofibroma was excluded due to the lack of biphasic growth pattern with hemangiopericytoma-like blood vessels. Fibrosarcoma was excluded due to the lack of malignant features, collagenous areas and herringbone pattern that characterize it. In addition, it typically lacks a significant inflammatory infiltrate.
There is no evidence of recurrence, malignant transformation, metastasis, or death reported with oral IMTs.
According to the World Health Organization, IMTs are classified as tumors of intermediate biological potential due to a tendency of local recurrence and small risk of distance metastasis.
The ALK (chromosome band 2p23) gene has been implicated in the pathogenesis of IMT supporting neoplastic origin of tumor. Approximately 50% of all IMTs have been associated with ALK positivity. Most of the previous oral IMT cases have been reported to be ALK negative. Indeed, a question has been raised whether ALK-positive IMTs are a distant clinicopathologic entity with neoplastic origin with more aggressive behavior and even potential for malignancy. The present case was ALK negative.
Including the present case, 28 cases of oral IMT have been reported [Table 1], with lesions occurring over a wide age range of 2–82 years and showing a 5:4 female predilection.,,,,,,,,,,,,,,,,,,,,,,,, The lesion typically presents as a firm, indurated swelling and does not produce significant systemic symptoms, unlike its counterpart in visceral organs. Intrabony presentation of IMT is rare. Only three cases have been reported. Brooks et al. described a resorptive effect of soft tissue on the underlying alveolar bone of the edentulous mandible. A computed tomography scan or magnetic resonance imaging was done in previous reports which characterized lesions with ill-defined infiltrative or erosive bony margins. There was no evidence of recurrence in any previous reports.
|Table 1: Clinical features of inflammatory myofibroblastic tumor cases in the oral cavity|
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In conclusion, IMT is a rare tumor of the gingiva, and diagnosis of the tumor or the differential diagnosis from other lesions of the gingival may be difficult. Even though being an extremely rare neoplasm, oral IMT should be included in the differential diagnosis of localized gingival enlargement mimicking oral hyperplastic/reactive lesions.
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.
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Conflicts of interest
There are no conflicts of interest.
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