Multiple Hereditary Exostoses

Abstract

HistoryThis is a case of a 50-year-old male with worsening pain over the past 8 years in both the right upper extremity and right lower extremity. The patient, of note, did not have any neck pain. On clinical examination, there was mild right upper extremity weakness (4/5) and abnormal reflexes in the right upper extremity and right lower extremity. There was mild right lower extremity weakness.Given the neurologic symptoms, radiographs were obtained, including imaging of the axial skeleton. Radiologic findingsMultiple imaging studies were obtained. Some of the initial imaging studies obtained were radiographs of the spine. Lateral radiograph of the cervical spine demonstrated a large exostosis involving the posterior elements at the C2-3 level (Fig. 1). Additional radiographs of the chest and spine demonstrated additional sessile osseous exostoses involving the proximal left humerus and right scapula (Figs. 2 and 3).Additional imaging of the cervical spine was obtained to better evaluate the large ossific mass involving the posterior elements at C2-3. Sagittal reformatted and axial computed tomography (CT) images demonstrated a large, expansile, osseous lesion involving the posterior elements, with marked narrowing of the central canal (Fig. 4). Magnetic resonance (MR) imaging demonstrated marked compression on the spinal cord as seen on both the sagittal and axial images, with focal linear intrasubstance cord signal hyperintensity consistent with myelomalacia and cord atrophy (Fig. 5).The diagnosis was multiple hereditary exostoses with expansile osteochondroma at C2-3 with resultant marked cord compression and cord atrophy and myelomalacia. DiscussionHereditary multiple exostosis is a rare disorder characterized by multiple osteochondromas with the associated potential of malignant degeneration. A possible genetic mutation (EXT gene) was postulated as a cause of he-HSSJ (2005) 1:49-51 DOI 10.1007/s11420-005-0107-1 Fig. 1. Lateral radiograph of the cervical spine demonstrating a large, exophytic, osseous mass involving the posterior elements at the C2-3 level (arrow)