Sudden unexpected death due to a previously undiagnosed plasma cell dyscrasia

The plasma cell dyscrasias are a diverse group of disorders characterized by the production of a clonal paraprotein. Sudden death is a recognized complication of the plasma cell dyscrasias, most commonly in individuals with cardiac involvement by amyloidosis. However, the current forensic literature has no reported cases in which sudden death resulted from complications of a plasma cell dyscrasia that was first diagnosed by postmortem histologic examination. We present the case of a woman whose sudden and unexpected death resulted from a seizure. Postmortem examination revealed no evidence of trauma or a grossly identifiable natural disease process that would have accounted for her death. However, microscopic and immunohistologic studies revealed a previously undiagnosed plasma cell dyscrasia, the clonality of which was determined by immunohistochemical studies for immunoglobulin light chains, that was not associated with amyloid deposition. This case elucidates a previously unrecognized cause of sudden unexpected death and illustrates the importance of microscopic studies in selected cases examined in medical examiner/coroner offices.