Giant cell reparative granuloma of the mandibular condyle: A rare presentation and literature review

Giant cell reparative granuloma (GCRG) is an extremely rare occurrence in the mandibular condyle. Here we describe the case of a 41-year-old man with a GCRG of the right mandibular condyle. Clinical, radiographic, and magnetic resonance imaging was unable to confirm the pathologic process. Surgery was performed, during which 20 mm of vertical height of the condylar head and neck was resected, including the articular discs. A vertical ramus sagittal osteotomy was performed to reposition the neo-condyle into the fossa for reconstruction of the joint. The patient's condition has been stable for 18 months with no evidence of recurrence of the tumor. He has 42 mm of intermaxillary opening with no arthralgia or marked change in occlusion. Histopathologic evaluation of the resected specimen revealed a tumor situated in the superior area of the condyle that contained an abundance of multinucleated cells with eosinophilic collagenous tissue and hemorrhage around the fissure, indicating a diagnosis of GCRG. There are only seven other reported cases of GCRG occurring in the mandibular condyle. The differential diagnoses in these cases were brown tumor (hyperparathyroidism) and cherubism, which were excluded by blood tests, physical signs, and diagnostic imaging, including technetium bone scans and computed tomography. Surgical intervention with resection of the condyle and reconstruction using bone grafts or sliding ramus osteotomy is recommended in such cases. Keywords: Giant cell reparative granuloma, Mandibular condyle, Vertical sliding ramus osteotomy, Differential diagnosi

Regulation of outgrowth and apoptosis for the terminal appendage: external genitalia: development by concerted actions of BMP signaling

Extra-corporal fertilization depends on the formation of copulatory organs: the external genitalia. Coordinated growth and differentiation of the genital tubercle (GT), an embryonic anlage of external genitalia, generates a proximodistally elongated structure suitable for copulation, erection, uresis and ejaculation. Despite recent progress in molecular embryology, few attempts have been made to elucidate the molecular developmental processes of external genitalia formation. Bone morphogenetic protein genes (Bmp genes) and their antagonists were spatiotemporally expressed during GT development. Exogenously applied BMP increased apoptosis of GT and inhibited its outgrowth. It has been shown that the distal urethral epithelium (DUE), distal epithelia marked by the Fgf8 expression, may control the initial GT outgrowth. Exogenously applied BMP4 downregulated the expression of Fgf8 and Wnt5a, concomitant with increased apoptosis and decreased cell proliferation of the GT mesenchyme. Furthermore, noggin mutants and Bmpr1a conditional mutant mice displayed hypoplasia and hyperplasia of the external genitalia respectively. noggin mutant mice exhibited downregulation of Wnt5a and Fgf8 expression with decreased cell proliferation. Consistent with such findings, Wnt5a mutant mice displayed GT agenesis with decreased cell proliferation. By contrast, Bmpr1a mutant mice displayed decreased apoptosis and augmented Fgf8 expression in the DUE associated with GT hyperplasia. These results suggest that some of the Bmp genes could negatively affect proximodistally oriented outgrowth of GT with regulatory functions on cell proliferation and apoptosis. The DUE region can be marked only until 14.0 dpc (days post coitum) in mouse development, while GT outgrowth continues thereafter. Possible signaling crosstalk among the whole distal GT regions were also investigated