Inherited craniofacial fibrous dysplasia

Autosomal dominant mesomandibular fibro-osseous dysplasia: a self-resolving inherited fibro-osseous lesion of the jaws

A hereditary congenital condition characterized by a fibro-osseous lesion sharing some features with fibrous dysplasia and affecting the middle aspect of the mandible is presented. The condition was initially described as congenital monostotic fibrous dysplasia in two siblings, a male and a female. However, there is sufficient evidence that the disorder is autosomal dominant since it has been encountered in two of four children, both males, of the female propositus and one child, a boy, of the male propositus. All patients presented at birth or right after birth with enlargement of the middle part of the mandible. Radiographs from affected individuals have shown mesomandibular enlargement with irregular trabeculation akin of “ground-glass” appearance. Histologically, samples from all patients revealed woven bone proliferation in a cellular fibroblastic stroma. Interestingly, the originally described siblings, now in their 30s, have no evidence of jaw lesions either radiographically or clinically, thus indicating that the condition is self-limiting or self-resolving. An autosomal dominant mode of inheritance with apparent male predilection is favored. The molecular basis of this condition is currently unknown. However, the location of the lesions in the middle aspect of the mandible suggests dysregulation of Bone Morphogenetic Protein (BMP) signaling since BMPs regulate mandibular morphogenesis in utero, particularly in the medial region as well as postnatal bone remodeling. Immunohistochemical evaluation for a BMP-binding protein Twisted Gastrulation (TWSG1) revealed mosaic pattern of staining, with some cells, including osteoclasts, strongly stained and others exhibiting faint or no staining, thus supporting active regulation of BMP signaling within the lesion. Future investigations will determine if dysregulation of BMP signaling plays a causative role or rather reflects secondary activation of repair mechanisms and/or bone remodeling.

Fibrous dysplasia

Fibrous dysplasia is a developmental disorder of bone that can present in a monostotic or polyostotic form. Primarily affecting adolescents and young adults, it accounts for 7% of benign bone tumors. Many of the asymptomatic lesions are found incidentally; the remainder present with symptoms of swelling, deformity, or pain. Fibrous dysplasia has been associated with multiple endocrine and nonendocrine disorders and with McCune-Albright and Mazabraud's syndromes. The etiology remains unclear, but molecular biology suggests a mutation in the G(s)alpha subunit and activation of c-fos and other proto-oncogenes. Fibrous dysplasia has a characteristic radiographic appearance. Most cases do not require intervention, but those that do usually are managed surgically with curettage, bone grafting, and, in some cases, internal fixation. When some intervention is necessary but surgery is not practical, treatment is with bisphosphonates. The prognosis generally is good, although poor outcomes are more frequent in younger patients and in those with polyostotic forms of the disease. The risk of malignant transformation is low.

Clinical and radiological evaluation of cherubism: a sporadic case report and review of the literature

Many cases have been published on cherubism since Jones described it first time in three children of the same family [Am. J. Cancer 17 (1933) 946]. Cherubism is an autosomal-dominant disorder in which the normal bone is replaced by cellular fibrous tissue and immature bone. Extracranial skeletal involvement is rarely seen in hereditary and non-hereditary forms of the disorder. The mandible is the most severely affected craniofacial component, in which uncontrolled growth of the malady deteriorates the aesthetic balance of the face. Bilateral swelling of the cheeks, mandibular enlargement and maxillary spongious hypertrophy cause orbital manifestations and tendency of eyes looking up to the sky. Thus, the pathognomic clinical feature resembles the appearance of "raised to heaven" Renaissance cherubs. The sporadic case concerns a child affected by cherubism. Radiographic and clinical data of the patient are presented and brief review of the literature is included.

Benign fibro-osseous lesions: a review of current concepts

The benign fibro-osseous lesions (BFOL) represent a clinically diverse group of disorders of bone that share similar histopathologic features. As a group, they are relatively common in the craniofacial complex, especially the jaws. Although the general concept of BFOL is relatively well known, specific diagnostic interpretation of individual cases is often challenging. New concepts and controversies have arisen over the past 10 to 15 years regarding classification and diagnostic criteria. However, among the new theories and contentions, there is now essential agreement that the osseous dysplasias represent a single disease process, while the so-called "juvenile active ossifying fibroma" and other "aggressive," "active," "psammomatoid" ossifying/cementifying fibromas remain controversial. This review is presented to update the surgical pathologist on the various entities comprising the spectrum of BFOL and to examine the criteria for their diagnosis.

Cranio-facial fibrous dysplasia in a 38-year-old African woman: a case history

A 38-year-old woman sought treatment with cranio-facial dysplasia involving the cranium, maxilla and the mandible. Her chief complaint was a mandibular swelling, which had appeared about 2 years previously, had gradually enlarged, and was associated with spontaneous pain. X-ray film examination revealed a ground-glass opacity with blurred demarcation and a 99 Tc medronate bone scan disclosed an increase in tracer uptake in the cranium, maxilla and mandible. The rest of the skeleton was not affected. Histological examination of the lesions revealed solid proliferation of spindle-shaped cells associated with islands of osteid and bone trabecullae with Chinese letter pattern and numerous multinucleated giant cells consistent with fibrous dysplasia. The continued osteoblastic activity of involved bones, coupled with the medical condition of the patient, restricted the management of the patient to largely supportive and palliative care.

Fibrous dysplasia and cherubism as an hereditary familial disease. Follow-up of four generations

Five cases of dysplasia of the jaws in one family which has been under our observation since 1970 are reported. The disease appeared as a mixed display of jaw lesions, in some members as fibrous dysplasia and in others as cherubism. We were able to trace the disorder through an unbroken line of four generations, and thus to demonstrate autosomal dominant inheritance. Cytogenetic analysis performed on three members of this family revealed a significantly increased rate of chromosomal breakage.