Monoclonal gammopathy of clinical significance with Cervical spondylotic myelopathy presenting as severe paralysis: a case report

Background: Cervical spondylotic myelopathy (CSM) is a progressive age-related degenerative disease. The natural course of CSM is usually marked by gradual deterioration in motor and sensory function, with a fixed parallel period. Therefore, CSM with severe progressive lower limb motor and bowel and bladder dysfunction is extremely rare. Monoclonal gammopathy (MG) is when abnormal B cell clones produce a monoclonal immunoglobulin in serum and urine. If it causes damage to multiple tissues or organs, it is known as Monoclonal gammopathy with clinical significance (MGCS). It is well established that Monoclonal gammopathy of undetermined significance (MGUS) causes peripheral neuropathy; however, no significant association was found with neurological disorders such as cerebellar ataxia, CNS demyelinating diseases, and motor neuron diseases. To the best of our knowledge, patients with CSM combined with MGCS presenting as severe paraplegia are sporadic. Case presentation: A 77-year-old man presented with progressive numbness of the trunk and lower extremities and weakness in his limbs for 11 months. Seven months ago, he complained of worsening symptoms and walking instability, developed to be unable to walk independently. The patient's most remarkable symptom was paralysis. We diagnosed myelopathy due to cervical disc herniation. Furthermore, we diagnosed MGCS because of the Bone marrow aspiration and flow cytology results. He was performed C7 Anterior cervical corpectomy decompression and fusion (ACCF). Three months after the operation, the patient showed improvement in symptoms. Conclusion: We report that a severely paralyzed CSM patient was diagnosed with MGCS and peripheral neuropathy. Few CSM patients exhibit severe paralysis and bowel and bladder dysfunction. The relationship between MGCS and peripheral neuropathy has been established, but there is still no firm evidence of a link with central nervous system injury. We began to suspect a link between the patient's clinical symptoms and MGCS. In patients with severe paralysis with CSM, early intervention to improve neurofunction is the most crucial issue. The changes in intramedullary signal on MRI sometimes do not indicate a worse prognosis; aggressive surgical treatment is necessary. Differentiating diagnosis and finding the primary etiology is therefore critical. We provide a new way of thinking for surgeons, emphasizing the importance of multidisciplinary collaboration.