CENTRAL ODONTOGENIC FIBROMA IN ASSOCIATION WITH BROWN TUMOR OF HYPERPARATHYROIDISM IN A PATIENT WITH NF1 AND RENAL FAILURE

Abstract

<h3>Objective</h3> Neurofibromatosis type 1 is an autosomal dominant disorder caused by mutations in the NF1 gene at chromosomal location 17q11.2. We present a patient with bone abnormalities and a myriad of lesions secondary to his redeveloping renal failure and NF1. <h3>Clinical Presentation</h3> A 21-year-old male renal transplant recipient with NF1 presented with painless masses and large, irregular radiolucent lesions in the maxilla and mandible. The bone was generally "moth-eaten" with a sparse trabeculation pattern. <h3>Intervention and Diagnosis</h3> Histologic examination of an incisional biopsy of the left mandibular lesion revealed two types of tissue with distinct histologic features. Approximately 3/4ths of the specimen was made up of variably cellular dense fibrous connective tissue interspersed with numerous inactive islands and cords of odontogenic epithelium. The remaining specimen consisted of abundant multinucleated giant cells embedded within a highly cellular stroma containing extravasated erythrocytes and hemosiderin. Throughout the specimen, seams of lace-like osteoid and irregular trabeculae of woven bone were noted. The lesion was diagnosed as a central odontogenic fibroma (COdF) in association with a central giant cell lesion, most consistent with brown tumor of hyperparathyroidism. The bone changes were interpreted to be highly suggestive of renal osteodystrophy. <h3>Conclusion</h3> Around 30 cases of hybrid central giant cell granuloma-like lesion in association with central odontogenic fibroma have been reported. This, to the best of our knowledge, is the first reported case of brown tumor in association with COdF. It has been proposed that a primary COdF induces a reactive giant cell response, however, this is unlikely here, given that the primary tumor was probably a ‘brown tumor'. Our case illustrates the point that the giant cell component may be the initiating entity in these hybrid lesions.