Anterior, extracanalar, cervical spine osteochondroma associated with DISH: description of a very rare tumor causing bilateral vocal cord paralysis, laryngeal compression and dysphagia. Case report and review of the literature

INTRODUCTION: Osteochon - dromas are common benign bone tumors, rarely involving the spine. BACKGROUND: Osteochondroma account for about 35% of bone benign tumors and 9% of all bone tumors. Spinal involvement is de - scribed in 1%-4% of cases and their origin from the anterior surface of cervical vertebral bodies is exceedingly rare. AIM: We describe the rare case of an osteo - chondroma arising from the anterior surface of the C4 and C5 vertebral bodies, and not involv - ing the spinal canal, in a 68-year-old male pa - tient suffering from Diffuse Idiopathic Skeletal Hyperostosis (DISH). MATERIALS AND METHODS: The patient pre - sented with acute onset of respiratory distress due to laryngeal compression exerted by the le - sion, dysphagia and paralysis of left vocal cord. Imaging revealed the unusual lesion compress - ing and dislocating the air ways. An anterior ap - proach to cervical spine was performed to re - move the tumor. RESULTS: Postoperatively, the patient sus - tained a progressive improvement of respiratory function and recovery of the vocal cord paralysis. DISCUSSION: We believe that this case holds some interesting peculiarities: firstly, the anterior location of a cervical osteochondroma could be considered exceptional; yet, the re - sulting clinical picture should be remembered for differential diagnosis. Secondly, we hypoth - esized a possible correlation between the tu - morigenesis of osteochondroma and the co-ex - istence of DISH. Indeed, the abnormal bone turnover in cervical segments due to DISH could explain the unusual occurrence of osteo - chondromas in adult age. CONCLUSIONS: The occurrence of an osteo - chondroma should be considered in patients suffering from DISH and harbouring large osteo - phytes.