[Desmoplastic fibroma of the zygoma]

Desmoplastic fibroma of the mandible: a rare gnathic bone tumor with a review of the literature

Desmoplastic fibroma (DF) is a rare bone tumor, which is known to involve mostly the gnathic bones. In this setting, the clinical presentation is usually represented by a bulging tumor of the face. Radiologically, the tumor is usually characterized by an expansile lytic bone lesion. The histopathology of the tumor shows a poorly circumscribed hypocellular lesion rich in collagen fibers with interspersed spindle cells having bland nuclear chromatin. Despite the lack of mitoses and nuclear pleomorphism, DF has an aggressive nature, presenting as a destructive growth causing entrapment of neuro-vascular bundles, sinusitis, or trismus. Some cases of DF show mutations in the adenomatous polyposis coli pathway shown by nuclear localization of the β-catenin protein. Few reports showed an association with tuberous sclerosis, though most of these cases were sporadic. We discuss a rare case of desmoplastic fibroma involving the mandible, and a review of the literature of the DF cases involving the gnathic bones.

Desmoplastic Fibroma, Report of a Rare Case in Infraorbital Rim

Desmoplastic fibroma (DF) is a rare and locally aggressive intraosseous tumor with unknown etiology. The mandible is the common site of involvement in the maxillofacial region. However, it is believed that DF can arise in any bone of the body. A wide age distribution has been reported for DF occurrence, extending from birth to the sixth decade of life, with a peak incidence at 10 to 19 years of age. In this study, diagnostic and therapeutic management of a 6-year-old girl with a desmoplastic fibroma of the inferior orbital rim and zygomatic buttress are discussed. Cone beam computed tomography (CBCT) revealed a mixed lesion in infraorbital rim, which had ill-defined borders and a straight thick bony septum inside the lesion. It also involved the zygomatic process of maxilla and zygomatic bone. According to radiologic concepts, this rare lesion may mimic fibro-osseous, benign and especially malignant lesions. Regarding different treatment plans, identification of this lesion is essential. Furthermore, presence of coarse and irregular or straight septa along with some imaging criteria for malignant lesions such as destruction of the cortex, periosteal reaction and soft tissue invasion would be helpful to differentiate this lesion from malignant and multilocular benign lesions.