Primary cervical spine AL-κ amyloidoma: A case report and review of the literature.

Of the myriad of variants of amyloidoses where abnormally folded proteins damage native tissue, primary cervical spine amyloidoma represents one of the rarest forms. Since clinical presentations and imaging findings appear similar to other pathologies, including abscesses, metastatic lesions, and inflammatory lesions, a definitive diagnosis requires a biopsy with specific immunohistochemical stains. We present the first known case of primary cervical amyloid light-chain (AL)-κ subtype amyloidoma and compare the clinical presentations, imaging findings, treatment options, and immunohistochemical subtypes of primary, hemodialysis, and multiple myeloma cervical amyloidomas. Our case is of a 58-year-old man who developed neck pain radiating to the left arm with bilateral upper extremity weakness over several months. Magnetic resonance imaging revealed a circumferential C1-C2 mass extending into the neural foramina inducing severe mass effect. The patient underwent C2 laminectomy and resection of the lesion which was discovered during surgery to be completely epidural. Postoperatively, his pain and weakness improved. A complete work-up was negative for systemic amyloidosis or inflammatory conditions. In the setting of a long clinical history of hemodialysis, this patient required specific staining and laboratory testing to correctly diagnose his primary cervical AL-κ subtype amyloidoma. Cervical amyloidomas comprise a very small minority of amyloid pathology with an exceptional prognosis following successful surgical resection and stabilization. It is recommended these patients undergo surgical resection with appropriate characterization and a complete work-up to rule out systemic disease.
(© 2019 Japanese Society of Neuropathology.)