Cervical epidural plasmacytoma causing recurrent radiculopathy and revealing plasma cell leukemia

Background: Cervical epidural plasmacytomas are an uncommon manifestation of plasma cell dyscrasias and may mimic degenerative cervical spondylosis. Here, we report an epidural plasmacytoma discovered during reoperation for recurrent radiculopathy that led to the diagnosis of plasma cell leukemia (PCL). Case Description: A 76-year-old female underwent a C5-C7 anterior cervical discectomy and fusion for cervical spondylotic radiculopathy. After initial improvement, severe radiculopathy recurred 6 weeks later. During posterior C6-T1 decompression, a gray, friable epidural mass encasing the left C7 and C8 nerve roots was identified and completely resected. Histopathological examination demonstrated a kappa-restricted plasma cell neoplasm with a Ki-67 index of 80%. Positron emission tomography-computed tomography revealed multiple hypermetabolic osseous lesions, and a peripheral blood smear showed 26% circulating plasma cells, establishing the diagnosis of primary PCL. Radicular pain and arm strength improved after decompression and lesion resection, and hematologic/oncologic therapy was initiated. Conclusion: Rapidly recurrent radiculopathy after cervical surgery for degenerative disease should prompt consideration of nondegenerative etiologies. In this case, an aggressive systemic plasma cell dyscrasia required prompt hematologic evaluation and treatment.