title: A case of isolated amyloid light-chain amyloidosis of the radial nerve.
abstract: Peripheral nerve involvement may be the first sign of systemic amyloid light-chain (AL) amyloidosis, a rare disease. Physical examination and electrodiagnostic testing are the mainstays of peripheral neuropathy evaluation at presentation. Sural nerve biopsy is performed in conjunction with serum and urine protein evaluation to differentiate between focal and systemic disease. Systemic disease is treated with a combination of chemotherapy, steroids, and stem cell transplantation. Isolated peripheral nerve disease is extremely rare. The authors here report the case of an 80-year-old woman who presented with progressive right upper-extremity weakness due to right radial neuropathy discovered upon electrodiagnostic testing. Magnetic resonance neurography (MRN) revealed a focal lesion within the right radial nerve. She underwent radial nerve exploration and excision of an intraneural mass consisting of amyloid on histopathology, with mass spectrometry analysis diagnostic for AL amyloidosis. Noninvasive testing and clinical history did not suggest systemic involvement. This unique case of isolated peripheral nerve AL amyloidosis in the absence of signs and symptoms of systemic disease is described, and the literature demonstrating peripheral nerve involvement in AL amyloidosis is reviewed.
authors.affiliation: Department of Neurosciences, Division of Neurosurgery; and.
authors.forename: Ron Ron
authors.initials: RR
authors.lastname: Cheng
authors.affiliation: Department of Neurosciences, Division of Neurosurgery; and.
authors.forename: Ramin
authors.initials: R
authors.lastname: Eskandari
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina.
authors.forename: Cynthia T
authors.initials: CT
authors.lastname: Welsh
authors.affiliation: Department of Neurosciences, Division of Neurosurgery; and.
authors.forename: Abhay K
authors.initials: AK
authors.lastname: Varma
mesh_terms: D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D000075363:Immunoglobulin Light-chain Amyloidosis / Q000175:diagnosis*; D020425:Radial Neuropathy / Q000175:diagnosis*
keywords: AL = amyloid light chain; EMG = electromyography; FLC = serum free light chain; HDM = high-dose melphalan; IFE = immunofixation electrophoresis; MRN = magnetic resonance neurography; SCT = stem cell transplantation; SPEP = serum protein electrophoresis; STIR = short T1 inversion recovery; amyloidosis; intraneural amyloidoma; magnetic resonance neurography; mononeuropathy; peripheral nerve