Long-lasting fever of unknown origin preceding the diagnosis of intravascular lymphomatosis: a further case stimulates some remarks.

Neurological and skin involvements usually dominate the clinical presentation of intravascular lymphomatosis (IL), while fever is the most frequent general sign. However, an onset only characterized by fever of unknown origin (FUO) has been rarely reported. We would like to describe a further case of IL, which presented a long-lasting FUO before the diagnosis. At admission, physical examination detected hepatosplenomegaly without lymph nodes enlargement or dermatological or neurological abnormalities. Significant laboratory data included severe anemia, leukopenia, thrombocytopenia, and increased serum LDH. Moreover, a chest CT evidenced bilateral multiple pulmonary infiltrates and pleural effusion. After the development of proteinuria, a diagnosis of large B-cell intravascular lymphoma was made with a renal biopsy 10 months after the onset of the clinical manifestations. So far, more than 100 cases of IL have been reported and the diagnosis often turned out to be difficult, as clinical signs did not point to a lymphoproliferative disorder. This report confirms that FUO is not only frequently associated with IL but that it even marks the real onset of the disease. We are then tempted to conclude that undiagnosed fever is not so rare in IL and if we call it FUO, it is only because diagnosis is necessarily elusive and hence time-consuming.