Imaging Features of Intraosseous Myofibroma of the Jaws: A Case Report and Literature Review

Citation: Newaz ZA, Pannu V, Kennedy J, Barghan S, Kashtwari DN, et al. (2015) Imaging Features of Intraosseous Myofibroma of the Jaws: A Case Report and Literature Review. J Adv Radiol Med Image 1(1): 102 Volume 1 | Issue 1 Journal of Advances in Radiology and Medical Imaging Introduction The terminology regarding myofibroma has historically had some variation and confusion. Older terms reported in the literature include congenital fibrosarcoma, congenital generalized fibromatosis, congenital mesenchymal hamartomas, and infantile myofibroma/myofibromatosis. Differentiation between solitary and multicentric variants of the disease led to the distinction of myofibroma from myofibromatosis respectively [1]. The World Health Organization (WHO) classification of tumors report from 2002 [2] acknowledged this difference and categorized them under “fibroblastic/myofibroblastic tumors”. In the latest WHO classification from 2013, myofibroma was moved from this group to the perivascular tumor group, due to “morphologic continuum” between it and myopericytoma [3]. Myofibroma is a rare perivascular tumor that can present in soft tissue, or less commonly, intraosseously. A twelve year-old female patient’s case of myofibroma in the mandible is reported with clinical presentation, imaging findings, histologic findings, treatment, and short-term follow-up. A literature search was conducted to provide an update, and to tabulate imaging features of central myofibroma of the jaws to better understand the common features and demographic parameters of the relatively small number of cases that have been reported. All reported intraosseous maxillofacial sites are in the mandible with two cases in the maxilla. They can grow rapidly and exhibit other aggressive features. They tend to be seen predominantly in the first two decades of life. Broadly, the lesion appears well-defined, radiolucent/lowly attenuated on radiographs/CT respectively, with the possibility of expansion, cortical perforation, and internal calcification. Effects on teeth and neurovascular structures are variable. Better understanding of this rare condition may assist the radiologist in consideration to include myofibroma in the differential diagnosis if the imaging findings meet certain parameters. Myofibromas are benign mesenchymal perivascular tumors comprised of myoid tissue. They are predominantly seen in children, and can also develop in adults [4,5]. Among the more common locations are the head, neck and trunk. They are predominantly soft tissue tumors that arise within dermis, subcutis, or soft tissue, but intraosseous presentation is sometimes seen. The mandible is a common intraosseous site. Myofibromas can be solitary or multifocal, the latter mostly in the infant age group. Solitary variants are overwhelmingly more common. Visceral involvement is uncommon, but can present in generalized myofibromatosis, and prognosis has been reported to be unfavorable in such cases [5]. Histologic features include fascicles of plump, myoid spindle cells, with elongated nuclei and eosinophilic cytoplasm, and possible myxomatous fibrous connective tissue. There is usually presence of capillaries or perivascular cells. Immunohistochemical analysis is typically positive for smooth muscle actin (SMA) and/or muscle-specific actin (MSA) [5]. Most tumors have been described as radiolucent/low-attenuation, well-defined, and expansile, with possibility of internal calcification. A recent extensive review of fibroblastic and myofibroblastic tumors of the head and neck summarizes computed tomography (CT) and magnetic resonance (MR) imaging findings as follows: CT findings include variable density, occasional calcification, necrosis and bone erosion; MR characteristics include hypointense signal in T1-weighted images and hypoor hyperintense signal in T2-weighted images. The same review also describes contrast administration to yield a strong and peripheral signal, and includes the possibility of sclerotic margins in plain film around the radiolucent lesions [6]. It appears to be widely reported that complete surgical resection is typically successful (for solitary lesions) without significant adverse sequelae and that recurrence rates are low [7,8]. In the case of multiple lesions in infancy, spontaneous regression has been reported. Tumor regression may depend upon chemotherapy in multicentric life-threatening forms [6].