Literature Review, Case Presentation and Management of Non-ossifying Fibroma of Right Angle of Mandible: More Than just a Cortical Defect!

Abstract

Non-ossifying fibroma (NOF) of jaw bones are rare. While NOF is the most common benign bone tumor of long bones with pathognomonic radiological features and bear a tendency for self-regression, gnathic NOF appears to be comparatively larger in size and behave more aggressively. A 16 years old female patient reported with painless swelling of the right side of the face of 4 months duration. Radiographic analysis showed a unilocular radiolucent lesion of right angle of the mandible with ill-defined margins, cortical perforation and thinning of inferior border. The lesion was provisionally diagnosed as odontogenic keratocyst/unicystic ameloblastoma and incisional biopsy was performed. The histopathological features and immunohistochemical characteristics favored a diagnosis of NOF. The lesion was excised and reconstructed. The excised specimen confirmed the diagnosis. There are no signs of recurrence at 18 months follow-up. NOF should be considered in the differential diagnosis of uni-/multilocular radiolucencies of jaws particularly the posterior mandible.

Keywords: ER; FGFR1; Gnathic; Mandible; Non-ossifying fibroma; RAS.

Fig. 1

a Extraoral presentation showing mild facial asymmetry owing to swelling on the right side of the face, b Intraorally, there was slight obliteration of right gingivobuccal sulcus with severe malocclusion, c OPG revealing a well-defined unilocular radiolucency of right angle of the mandible with ill-defined margins, d 3D- reconstructed images of CT confirming the finding of plain radiography e Intra-operative view, showing solid tumor and exposed right inferior alveolar nerve, and f 3D- reconstructed images of CT after reconstruction

Fig. 2

Photomicrographs of H&E stained sections showing proliferation of bland spindle to stellate shaped cells with rich vascularity and no ossification, peripheral bone is also evident (a-40X, b&c-100X), numerous hemosiderophages (d-400X), foci of foamy histiocytes (e-100X) and multinucleated giant cells, (f-400X)

Fig. 3

Photomicrographs of IHC stained sections showing a CD68 positivity in histocytes and b SMA positivity in background vasculature and occasional spindle cells

Fig. 4

Schematic representation of the signalling pathways involved in the pathogenesis of NOF. FGFR-fibroblast growth factor, MEK-MAPK/ERK kinase, ERK-extracellular signal regulated kinase, M-CSF-macrophage colony stimulating factor, IL-1- interleukin-1, TNF-alpha- tumor necrosis factor-alpha, RANKL-receptor activator of nuclear factor kappa beta ligand, NF-neurofibromatosis-1