Calcifying Pseudoneoplasm of the Cervicomedullary Junction: Case Report and a Literature Review

BACKGROUND: Calcifying pseudoneoplasm of the neuroaxis (CAPNON) is a rare, slow-growing tumor of a fibro-osseous origin that may present anywhere in the neuroaxis. Although typically benign, symptoms of CAPNONs typically present secondary to compression and surrounding mass effect. Histologically, the tumor has the characteristics of a foreign body reaction with giant cells, ossification, and the formation of psammoma bodies. On imaging, they can easily be confused with malginant lesions such as chondrosarcoma or chondroblastoma or even more benign pathologies like meningioma. CASE DESCRIPTION: We present a case of a patient with an incidentally found calcifying pseudoneoplasm involving the cervicomedullary junction with further involvement of the vertebral artery and the hypoglossal nerve. We also review the literature on these tumors to date. CONCLUSION: Calcifying pseudoneoplasm of the neuroaxis is a slow-growing, benign, noninfiltrative lesion whose pathogensis and natural history remains unclear. It can appear anywhere in the neuroaxis and does not have a prevelant location. Because of the indolent course and relative rarity of this tumor, there are no current guidelines on the immediate and long-term management of CAPNONs. This entity, although quite rare, should be considered in the differential for calcified lesions at the cervicomedullary junction. The consensus for treatment of CAPNONs when symptomatic is surgical resection.