Massive ossifying fibroma of the mandible in a child

Minu Bajpai, P. Goel, O. Bhutia,¹ Anand Gupta,¹ A. Seth,² A. K. Gupta,² and D. K. Pawar³

CASE REPORT

A 10-year-old boy with a known sickle-cell trait, had a four-years history of a painless, slowly enlarging tumor of the lower jaw [Figure 1] was referred from the department of dental surgery where incision biopsy and digital subtraction angiography (DSA) was done. The mass was non-tender, non-fluctuant, hard and covered with intact and uninvolved mucosa inside the oral cavity and skin externally. There was no paresthesia or hypoesthesia of lower lip or face. Severe microcytic and hypochromic anemia with hemoglobin of 4.9 g/dL with anisopoikilocytosis was reported. Pencil cells could be demonstrated in the peripheral smear. Hb HPLC was suggestive of a sickle-cell trait (Hb A0=62.6%, Hb F=0.7%, Hb S=27.1%, Hb A2=3.2%).

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On computed tomography (CT) scan, it was a large, very well defined, single, expansile lesion, 17×9.5×12 cm, involving the whole of the body and the antero-inferior hemi-ramus on the right side. The matrix was calcified, and the teeth were displaced to the periphery of the lesion. The inner cortex of the mandible was thin but intact. Bilateral temporo-mandibular joints and the maxilla were spared. There was no cervical adenopathy. The CT angiography showed that the tumor was being fed by bilateral facial and lingual arteries. The incision biopsy was consistent with an ossifying fibroma. It revealed the collagenous nature of the stroma with contained spindle fibroblastic cells. The stroma was highly vascular. The partially interconnecting trabeculae of woven bone and the presence of osteoblasts on their surfaces were distinguishing.

The patient was intubated by the nasal route and positioned supine with a roll under the upper back to extend the neck slightly. The incision given was completely intra oral extending from the right retromolar region to the left retromolar region at mucogingival junction. The lower lip was gradually dissected off the tumor surface circumferentially till we reached all around the mass. Both the rami were divided proximal to the tumor margins with a gigley saw, and the tumor removed by gradually dissecting it off the remaining soft-tissue attachments. The inner cortex of the mandible was thinned out but free of the tumor mass. A U shaped piece of bone was removed from the inner cortex of resected specimen as free bone graft and used to reconstruct the mandible. Reconstruction of the mandible was done using 2.0 mm high profile titanium plate (Synthes®) and free bone graft from the uninvolved mandibular bone. Tongue musculature (hyoglossus and genioglossus) and mylohyoid muscles were tied around the reconstructed mandible using 2-0 proline suture to provide normal function of mandible and associated structures and importantly preventing the fall back of the tongue.

The patient was kept intubated for 2 days to prevent asphyxia due to fall back of tongue and pharyngeal edema. The drain was removed on the fourth post-operative day. The lower jaw was supported by dynaplast strapping. The patient was started on physiotherapy. Drooling of saliva was present in immediate post-op due to boggy lower lip but gradually the oral seal was achieved in 6 weeks.

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At 6-week follow-up after surgery, the patient could elevate and depress his lower jaw over amplitude of 3.5 cm. Normal tongue movements were achieved together with adequate competency of lips [Figure 2]. The soft tissues started contracting to give a more normal appearance. The plain radiograph showed no signs of resorption of the bone graft. Reconstruction is planned in two stages. Stage one (temporary) with bone plates and free bone graft from uninvolved bone as a patient had sickle-cell anemia and another surgical site for permanent reconstruction may lead to increased anesthesia time and more blood loss. Stage two (permanent) is planned at the age of 18-20 years when his growth seizes, and better esthetics should be planned to correct the residual deformity. Permanent reconstruction will be done using free fibula transfer (microvascular surgery) and dental implants for final oral rehabilitation.