Multiple myeloma in a patient with fever of unknown origin and cholestasis.

The differential diagnosis of fever of unknown origin includes infectious diseases, malignancies and connective tissue diseases. Multiple myeloma is not usually included in the differential diagnosis, nor is it considered a frequent cause of cholestasis in the absence of amyloidosis. We report a case of multiple myeloma in a patient presenting with a long-standing fever and cholestasis. The patient underwent a long and unfruitful series of diagnostic procedures, including liver biopsy. The clue to the diagnosis, established with a marrow biopsy, was the presence of a paraprotein in the serum.