Focal Fibronodular Heterotopic Ossification

Abstract

Progressive extraskeletal ossification is the defining feature of a group of very rare genetic syndromes, including fibrodysplasia ossificans progressiva and progressive osseous heteroplasia. Recent advances in human molecular genetics have enabled the molecular characterization of disease-causing mutations for some of these conditions1,2. Despite our increasing understanding of the biochemical etiology of heterotopic ossification syndromes and newly applicable molecular genetic screening tools, individual patients with progressive heterotopic ossification still pose a difficult diagnostic challenge. We report the case of a female patient with a four-decade history of recurrent, progressive heterotopic ossification limited to the right hemicorporeum. This condition, which does not meet the clinical or molecular diagnostic criteria of any known syndrome, represents a new syndrome of heterotopic ossification, which we have named focal fibronodular heterotopic ossification. Our patient was informed that data concerning the case would be submitted for publication. A sixty-three-year-old right-hand-dominant woman presented to our institution for evaluation and treatment of a complex deformity of the right upper extremity. Distinctive features of the deformity at the time of presentation included multiple firm nodular soft-tissue masses located on the dorsal and volar surfaces of the right hand and wrist, involving the thumb, index finger, and long fingers. The patient had severe contractures of the index finger and first web space in areas of particularly large and dense nodule formation; small skin ulcerations that appeared to be chronic and infected were seen in these areas and at the volar base of the first metacarpal (Figs. 1-A, 1-B, and 2). The patient had a concomitant dense sensory and motor neuropathy of the median nerve of the right hand. Full physical examination revealed other areas of hard, nodular swelling, specifically in the patient's right shoulder, right upper arm, right lateral forefoot, and right iliac crest. Notably, the …