Autopsy of malignant paraganglioma causing compressive myelopathy due to vertebral metastases

Paraganglioma is a neuroendocrine tumor arising from extra-adrenal sites in the peripheral nervous system. Although malignant paraganglioma is known to metastasize to bones, including vertebral bodies, there is little literature on the compressive myelopathy accompanied by sphincter dysfunction; to our knowledge, only 12 cases have been reported. Moreover, neuropathological investigations of the spinal cord in this state have not been well-documented. This autopsy report describes a 55-year-old man with malignant paraganglioma and compression myelopathy caused by vertebral metastasis. The present case showed a gradual numbness and a sudden onset of irreversible paraplegia with sphincter dysfunction, which were not palliated these neurologic dysfunctions despite radiotherapy. Computed tomography (CT) revealed multiple metastases to the bones, lymph nodes, and lungs when he was diagnosed with malignant paraganglioma. At the same time, he had numbness, and magnetic resonance imaging (MRI) showed multiple diffuse metastatic lesions in the vertebral bodies. Following abrupt onset of paralysis, MRI showed fractured third and sixth thoracic vertebral bodies. An autopsy revealed residual vertebral metastases with fractures of the third and sixth thoracic vertebral bodies, resulting in compressive myelopathy at the fourth thoracic segment, which was characterized by complete spinal cord destruction. Destructive spinal cord lesion-induced secondary degeneration was observed in the gracile fasciculus at the rostral side and in the pyramidal tract at the caudal side, which showed Wallerian degeneration. Such pathology was consistent with the presenting neurological symptoms, including paraplegia and somatic sensory loss below the fourth thoracic spinal cord segment. Although it is difficult to identify the pathognomonic morphological changes responsible for the sphincter dysfunction, the present case suggests a supranuclear dysregulation of the somatosensory and central autonomic nervous systems involved in urination and defecation. Based on a review of the literature and the features of the present case, paraganglioma can metastasize aggressively even with a low pathological grading. This case of vertebral metastasis as a result of malignant paraganglioma may not be extraordinary but the autopsy report is rare. This autopsy revealed transverse myelopathy as a result of malignant vertebral metastasis of malignant paraganglioma.