Atypical presentations of primary amyloid neuropathy

Primary amyloidosis (AL) may be complicated by peripheral neuropathy in 15-35% of cases. We report on four patients with atypical neurological presentations of AL neuropathy, whose diagnoses were delayed due to varied clinical presentations. The clinical presentation included painful sensory neuropathy (two patients), mononeuropathy multiplex (one patient), and primary demyelinating polyneuropathy (one patient). The latter two types of presentation have not been reported previously. The diagnosis was established by fat pad biopsy in two patients, lymph node biopsy in one, and sural nerve biopsy in one. Two patients were treated with high-dose melphalan followed by stem cell rescue, and one was treated with oral melphalan and prednisone. All three cases experienced stabilization of neuropathic symptoms. We report these cases in order to raise awareness of the varied clinical presentation of AL neuropathy.