Optic neuropathy and macular chorioretinal folds caused by orbital cherubism

Multiple versus solitary giant cell lesions of the jaw: Similar or distinct entities?

The majority of giant cell lesions of the jaw present as a solitary focus of disease in bones of the maxillofacial skeleton. Less frequently they occur as multifocal lesions. This raises the clinical dilemma if these should be considered distinct entities and therefore each need a specific therapeutic approach. Solitary giant cell lesions of the jaw present with a great diversity of symptoms. Recent molecular analysis revealed that these are associated with somatic gain-of-function mutations in KRAS, FGFR1 or TRPV4 in a large component of the mononuclear stromal cells which all act on the RAS/MAPK pathway. For multifocal lesions, a small group of neoplastic multifocal giant cell lesions of the jaw remain after ruling out hyperparathyroidism. Strikingly, most of these patients are diagnosed with jaw lesions before the age of 20 years, thus before the completion of dental and jaw development. These multifocal lesions are often accompanied by a diagnosis or strong clinical suspicion of a syndrome. Many of the frequently reported syndromes belong to the so-called RASopathies, with germline or mosaic mutations leading to downstream upregulation of the RAS/MAPK pathway. The other frequently reported syndrome is cherubism, with gain-of-function mutations in the SH3BP2 gene leading through assumed and unknown signaling to an autoinflammatory bone disorder with hyperactive osteoclasts and defective osteoblastogenesis. Based on this extensive literature review, a RAS/MAPK pathway activation is hypothesized in all giant cell lesions of the jaw. The different interaction between and contribution of deregulated signaling in individual cell lineages and crosstalk with other pathways among the different germline- and non-germline-based alterations causing giant cell lesions of the jaw can be explanatory for the characteristic clinical features. As such, this might also aid in the understanding of the age-dependent symptomatology of syndrome associated giant cell lesions of the jaw; hopefully guiding ideal timing when installing treatment strategies in the future.

SH3BP2-related fibro-osseous disorders of the maxilla and mandible: A systematic review

Cherubism is a disorder of bony overgrowth of the jaws that manifests in childhood. SH3BP2 gene variants have been associated with cherubism; this gene plays a major role in bone homeostasis. Due to its rare occurrence, there is as yet no comprehensive understanding of the natural history and clinical course of the disease. The aim of this review was to compile and analyze all cases of SH3BP2-related cherubism and cherubism-like disorders. Thirty publications were identified, including 92 individuals from 34 families, who were diagnosed with SH3BP2-related fibro-osseous lesions of the jaw. Only 15% of cases included in this review had no known family history of the disease. The distribution of cherubism was equal with respect to biological sex. Missing teeth were reported in 38% of cases. Lesions were restricted to the mandible in 36% of cases and involved both the maxilla and mandible in 54% of cases. The clinical phenotypes reported in the articles analyzed varied greatly in detail, making comparisons between studies and conclusive analysis difficult. Further work is necessary to describe the connection between SH3BP2 gene variants and cherubism in order to advance its diagnosis and treatment.

Staphyloma-related chorioretinal folds

Purpose

To report a case of bilateral idiopathic chorioretinal folds that seemed to be related to an atypical staphyloma.

Observations

A 49-year old man without medical history consulted for slight vision loss and metamorphopsia in the left eye. The ophthalmologic examination revealed moderate myopia and bilateral chorioretinal folds in the posterior pole, confirmed by multimodal imaging. Orbital and systemic examinations ruled out all the known etiologies of chorioretinal folds. 3-D optical coherence tomography and B-scan suggested that the folds were related to an atypical staphyloma that developed in the temporal part of the fundus, while sparing the peripapillary area. The peripapillary area, spared by the staphyloma process, appeared as a “dome-shaped disc” compared to the staphylomatous area.

Conclusion and importance

This case suggests that myopic patients with unusual staphyloma located outside the peripapillary area could develop chorioretinal folds.

Second-Generation SYK Inhibitor Entospletinib Ameliorates Fully Established Inflammation and Bone Destruction in the Cherubism Mouse Model

Cherubism is a craniofacial disorder characterized by maxillary and mandibular bone destruction. Gain-of-function mutations in the SH3-domain binding protein 2 (SH3BP2) are responsible for the excessive bone resorption caused by fibrous inflammatory lesions. A homozygous knock-in (KI) mouse model for cherubism (Sh3bp2^KI/KI ) develops autoinflammation resulting in systemic bone destruction. Although administration of the TNF-α blocker etanercept to neonatal Sh3bp2^KI/KI mice prevented the disease onset, this therapy was not effective for adult Sh3bp2^KI/KI mice or human cherubism patients who already had lesions. Because genetic ablation of spleen tyrosine kinase (SYK) in myeloid cells rescues Sh3bp2^KI/KI mice from inflammation, we examined whether SYK inhibitor administration can improve fully developed cherubism symptoms in adult Sh3bp2^KI/KI mice. Entospletinib (GS-9973) was intraperitoneally injected into 10-week-old Sh3bp2^KI/KI mice every day for 6 weeks. Treatment with GS-9973 improved facial swelling and histomorphometric analysis of lung and liver tissue showed that GS-9973 administration significantly reduced inflammatory infiltrates associated with decreased levels of serum TNF-α. Micro-computed tomography (μCT) analysis showed that GS-9973 treatment reduced bone erosion in mandibles, calvariae, and ankle and elbow joints of Sh3bp2^KI/KI mice compared to Sh3bp2^KI/KI mice treated with dimethyl sulfoxide (DMSO). Taken together, the results demonstrate that administration of the SYK inhibitor ameliorates an already established cherubism phenotype in mice, suggesting that pharmacological inhibition of SYK may be a treatment option for cherubism patients with active disease progression. © 2018 American Society for Bone and Mineral Research.

Ophthalmic manifestations of cherubism

Cherubism is a rare craniofacial disorder characterized by progressive replacement of mandibular and maxillary bone with multicystic fibro-osseous tissue, potentially resulting in significant deformity and morbidity. The severity of the disorder is variable; more advanced disease may affect the orbit and impact vision. We detail the ophthalmological findings in 2 patients, 7 and 8 years of age, with cherubism.

Bone marrow transplantation improves autoinflammation and inflammatory bone loss in SH3BP2 knock-in cherubism mice

Cherubism (OMIM#118400) is a genetic disorder in children characterized by excessive jawbone destruction with proliferation of fibro-osseous lesions containing a large number of osteoclasts. Mutations in the SH3-domain binding protein 2 (SH3BP2) are responsible for cherubism. Analysis of the knock-in (KI) mouse model of cherubism showed that homozygous cherubism mice (Sh3bp2(KI/KI)) spontaneously develop systemic autoinflammation and inflammatory bone loss and that cherubism is a TNF-α-dependent hematopoietic disorder. In this study, we investigated whether bone marrow transplantation (BMT) is effective for the treatment of inflammation and bone loss in Sh3bp2(KI/KI) mice. Bone marrow (BM) cells from wild-type (Sh3bp2(+/+)) mice were transplanted to 6-week-old Sh3bp2(KI/KI) mice with developing inflammation and to 10-week-old Sh3bp2(KI/KI) mice with established inflammation. Six-week-old Sh3bp2(KI/KI) mice transplanted with Sh3bp2(+/+) BM cells exhibited improved body weight loss, facial swelling, and survival rate. Inflammatory lesions in the liver and lung as well as bone loss in calvaria and mandibula were ameliorated at 10weeks after BMT compared to Sh3bp2(KI/KI) mice transplanted with Sh3bp2(KI/KI) BM cells. Elevation of serum TNF-α levels was not detected after BMT. BMT was effective for up to 20weeks in 6-week-old Sh3bp2(KI/KI) mice transplanted with Sh3bp2(+/+) BM cells. BMT also ameliorated the inflammation and bone loss in 10-week-old Sh3bp2(KI/KI) mice. Thus our study demonstrates that BMT improves the inflammation and bone loss in cherubism mice. BMT may be effective for the treatment of cherubism patients.

Cherubism: report of three cases and literature review

PURPOSE

To report 3 cases of cherubism, one of whom underwent surgery for orbital manifestations, and to provide a literature review.

CASE REPORTS

Our patients were normal at birth and developed painless enlarging of the cheeks and jaws when they were 4-5 years old. Ophthalmologic examinations showed mild proptosis, superior globe displacement and inferior scleral show in all cases. Cases 2 and 3 had lower lid skin discoloration. Computed tomography (CT) scans demonstrated bilateral multicystic lesions in the maxilla and mandible with cortical thinning in all cases. In Case 3, left eye hyperglobus and anisometropic amblyopia was seen. In this case, the CT scan showed a round, well-defined and homogeneous mass, involving the anterior and superior walls of the maxillary sinus on the left side, extending into inferior orbit. Debulking of the mass was performed at the surgery. The pathologic findings were compatible with the diagnosis of giant cell reparative granuloma. He returned 1 year after surgery with recurrence of the mass.

DISCUSSION

A few cases were reported in the literature with histopathologically proven orbital cherubism. To our knowledge, lower lid skin discoloration in Cases 2 and 3 and anisometropic amblyopia in case 3 were not described elsewhere in cherubism cases. We recommend that all cases with cherubism must be examined by an ophthalmologist to diagnose and treat possible orbital manifestations.

Cherubism: best clinical practice

Cherubism is a skeletal dysplasia characterized by bilateral and symmetric fibro-osseous lesions limited to the mandible and maxilla. In most patients, cherubism is due to dominant mutations in the SH3BP2 gene on chromosome 4p16.3. Affected children appear normal at birth. Swelling of the jaws usually appears between 2 and 7 years of age, after which, lesions proliferate and increase in size until puberty. The lesions subsequently begin to regress, fill with bone and remodel until age 30, when they are frequently not detectable.

Fibro-osseous lesions, including those in cherubism have been classified as quiescent, non-aggressive and aggressive on the basis of clinical behavior and radiographic findings. Quiescent cherubic lesions are usually seen in older patients and do not demonstrate progressive growth. Non-aggressive lesions are most frequently present in teenagers. Lesions in the aggressive form of cherubism occur in young children and are large, rapidly growing and may cause tooth displacement, root resorption, thinning and perforation of cortical bone.

Because cherubism is usually self-limiting, operative treatment may not be necessary. Longitudinal observation and follow-up is the initial management in most cases. Surgical intervention with curettage, contouring or resection may be indicated for functional or aesthetic reasons. Surgical procedures are usually performed when the disease becomes quiescent. Aggressive lesions that cause severe functional problems such as airway obstruction justify early surgical intervention.

New retinal findings in cherubism

PURPOSE

To report three new retinal findings in a patient with cherubism.

PARTICIPANT

An 18-year-old male patient.

METHODS

Clinical examination and retinal scanning with spectral domain optical coherence tomography.

RESULTS

The spectral domain optical coherence tomography revealed inner retinal striae in the posterior pole of both eyes and a subfoveal vitelliform deposit in the left eye. There was an inferior retinoschisis in the left eye.

CONCLUSIONS

The inner retinal striae, subretinal vitelliform deposit, and retinoschisis extend the scale of retinal findings associated with orbital (facial) cherubism.

Une complication ophtalmologique du chérubisme

INTRODUCTION

Cherubism is a rare familial fibro-osseous lesion usually observed in children. The diagnosis is clinical and radiological. Outcome is generally favorable, but with a risk of ophthalmologic complications, especially lower eyelid retraction, proptosis, diplopia, displacement of eyeball and loss of visual acuity. Clinicians must be aware of these complications for proper detection and specific treatment.

OBSERVATION

We report a case of cherubism observed in a 10-year-old boy who presented exophthalmia with reduced visual acuity on the right due to reduction of the volume of the orbital cavity and compression of the optic nerve. Partial maxillectomy was required for decompression.

DISCUSSION

Cherubism can lead to various types of ophthalmologic complications. Exophthalmos and loss of visual acuity due to compression of the optic nerve are the most common. Surgery is generally not required, but can become crucial in selected patients.

Querubismo: relato de caso e revisão da literatura com aspectos imaginológicos

Querubismo é uma doença óssea hereditária não neoplásica caracterizada, clinicamente, por aumento indolor bilateral da mandíbula e maxilar em crianças, produzindo uma aparência querubínica. Pode ocorrer em casos isolados ou em membros de uma mesma família. Relatamos o caso de querubismo em uma menina sem história familiar, com lesões osteolíticas expansivas na mandíbula e maxila demonstradas em exames radiológicos.