Acute Plasma Cell Leukemia Presenting as Primary Hyperammonemic Encephalopathy.

Primary plasma cell leukemia (PPCL) is a rare form of multiple myeloma (MM) and is a rare aggressive disease with a median overall survival of 6 - 11 months. We present a case of acute hyperammonemic encephalopathy as the initial presentation of PPCL in a 78-year-old woman to highlight an atypical presentation of this disorder.