Non-familial cherubism: A case report with its surgical management.

Cherubism is an autosomal-dominant inherited syndrome; it starts in early childhood and involutes by puberty. It is characterized by excessive bone degradation of the jaws and development of fibrous tissue masses. Non-familial cherubism is a rare entity, which needs to be documented. This paper describes the findings of non-familial cherubism. An 11-year-old male patient reported with bilateral swellings of the jaws and unerupted teeth. Extensive gingival overgrowth, cherubic facial appearance, multilocular osteolytic lesions in radiographs and family history lead to the diagnosis of non-familial cherubism. Treatment included full mouth excision of the gingival tissue by gingivectomy with both manual instrumentation and electrosurgery. Patient is being monitored and recalled for frequent follow-ups. Dental practitioners need to be alert with patients presenting with gingival overgrowth.

INTRODUCTION

Cherubism is a rare disease of autosomal dominant inheritance characterized by painless, frequently symmetrical, enlargement of the jaws as a result of the replacement of bone with fibrous tissue.[1] Cherubism is caused by seven mutations in the gene encoding SH3-binding protein SH3BP2 on chromosome 4p16.3.[23] The SH3BP2 mutation is thought to lead to parathyroid hormone receptor signaling and Msx-1 activation. This results in a compartmentalization failure of the cap stage during the molar development leading to deregulation of bone formation and remodeling, development of multinucleated giant cells with abundant deposition of fibrohistiocytic tissues.[3]

CASE REPORT

An 11-year-old male patient of non-consanguineous parents came with the chief complaint of missing teeth in both upper and lower jaw. Patient gave a history of painless bilateral swelling in the mandibular region. Swelling arose at the age of approximately 3-4 years, which progressed rapidly until the age of 8 years. There was no history of a similar disease in any the parents or siblings. Prenatal and natal history revealed a normal full term pregnancy. There was no history of any drug therapy. Patient did not suffer from any serious illness, mental retardation or social inabilities. On clinical examination, it was noticed that swelling was more prominent on the right side, firm on palpation and non-tender. The extension of swelling was from the anterior part of ramus to mandibular premolar region on the right side and from the anterior part of ramus to mandibular molar region on the left side [Figure 1]. Both right and left submandibular lymph nodes were palpable. Gingiva was pink, firm, fibromatous, covering almost all the teeth [Figure 2]. Mandibular buccal vestibular fullness due to swelling in both right and left side was seen. Panoramic-radiograph [Figure 3] showed large, multiloculated soap bubble-like cavities at the angle and ramus of the mandible as well as thin vestibular cortical bone without involving condyles. These lesions were accompanied by displacement and impaction of erupted teeth and dental follicles. Incisal one-third of mandibular incisors were visible in the oral cavity, all the other teeth were impacted.

Figure 1

Patients profile of patient diagnosed with cherubism

Figure 2

Pre-operative facial view showing generalized gingival enlargement covering teeth surfaces

Figure 3

Pre-operative panoramic view showing numerous displaced and unerupted teeth

Serum alkaline phosphate, calcium and phosphorous levels were within the normal ranges. Histopathological evaluation of an incisional biopsy in right mandibular region showed highly vascular fibrous stroma with numerous multinucleated giant cells. The family, clinical, radiographic, laboratory and microscopic features suggested a diagnosis of non-familial cherubism. The treatment consisted of an external bevel gingivectomy in all quadrants using a scalpel and electro cautery. In between, gingivectomy was performed quadrant wise with adequate healing time [Figures 4 and 5]. Post-operatively healing was excellent with improvement in quality-of-life. Orthodontic treatment has been planned for the present case in the near future and follow-up visits are still in progress.

Figure 4

Pre-operative view of mandibular anteriors

Figure 5

Post-operative view after full mouth gingivectomy

DISCUSSION

Cherubism is a familial disease in which the trait is transmitted in an autosomal dominant fashion with 100% penetrance in males and 50-70% penetrance in females.[4] However, several isolated cases have been reported in the literature.[567] In our case, none of the patient's family member showed any occurrence of this disease. Thus, this report adds to few documented cases of non-familial cherubism. The radiographic appearance of cherubic lesions is characteristic; with bilaterally symmetrical, well-defined, multilocular radiolucency in the mandible that extends, from the region of the molar teeth toward the midline. Dental anomalies in the form of incomplete or non-development of teeth, root resorption and displacement or loss of teeth are frequently present.[15] Similar classical, radiographic appearances of cherubism such as bilateral large multiloculated soap bubble-like cavities at the angle and ramus of the mandible with thinning of vestibular cortical bone were seen in our case [Figure 3].

Differential diagnosis of cherubism includes craniofacial dysplasia, other giant cell containing fibro-osseous diseases such as brown tumor of hyperparathyroidism, giant cell tumor and central and peripheral giant-cell granuloma. The gene responsible for cherubism was recently mapped to the chromosome, 4p16.3. At the molecular level, cherubism and fibrous dysplasia are two different entities as they both result from different mutations. Cherubism results from a different mutation. Those in SH3-binding protein SH3BP2 (MIM 602104) on chromosome 4p16.3 that is different from that of craniofacial fibrous dysplasia and hence, the two are distinct entities at the molecular level.[38] Central giant-cell granuloma may be excluded on clinical grounds because it presents itself slightly later (between 10 and 30 years of age); it is not a bilateral condition, is not inherited, does not regress in adulthood and usually involves predominantly the anterior mandible. Giant-cell tumor resembles cherubism histopathologically, but it is unusual in the jaws, affects patients between the ages of 20 and 40 years and is seen unilaterally. On the other hand, bone changes in hyperparathyroidism rarely affect the jaw in an isolated manner and produce abnormal serum calcium, phosphorus and alkaline phosphatase levels. Cherubism usually does not affect osseous metabolism; bone markers are generally at normal levels with respect to age.[910]

Cherubism is generally a self-limiting condition and regresses with age, treatment depend on the clinical course of the disease and is indicated only in the cases of esthetic or functional problems. As our case was characterized by functional impairment in speech, mastication, unerupted teeth and unsatisfactory esthetic looks, surgical treatment was opted for. Psychological benefits because of cosmetic improvement outweigh the probability of recurrences in such severe cases. After gingivectomy, most of the teeth are now visible in the oral cavity which has aided in a variety of improvements such as mixed dietary habits, better phonetics and satisfactory looks with resultant improvement in quality-of-life. The diet of the patient improved after surgical treatment with the inclusion of raw fruits, vegetables and non-vegetarian food. This resulted in weight gain of the patient with an increase from 45 kg at the time of diagnosis to 49 kg within 2 months of starting the treatment [Tables 1 and 2]. Parents of the patient also reported increased involvement in social activities and communication because of better phonetics and appearance. As, recurrences in such cases has been documented patient is still under observance through regular follow-up visits.

Table 1

Diet chart of the patient before surgical treatment

Table 2

Diet chart of the patient after surgical treatment