[Monoclonal component in visceral leishmaniasis: a rare association that can lead to misdiagnosis]

The detection of monoclonal components is exceptional in patients with visceral leishmaniasis (VL). The cases are here reported of two patients with VL in a non-endemic area and monoclonal components which posed problems for the differential diagnosis with other entities associated with the presence of paraproteins. The predominant clinical manifestations in both cases were general symptoms, fever and severe spleen enlargement. One patient had a monoclonal triple band in urine and the other several oligoclonal bands in serum. In the initial bone marrow aspiration smear no parasites were observed in any of the two cases but a remarkable plasmacytosis in one of them. The presence of increased serum titers of anti-Leishmania antibodies was the first demonstrative finding of VL. The diagnosis was confirmed with positive culture of Leishmania and therapy with pentavalent antimonials was successful in both cases. The different diagnostic possibilities are discussed and the possibility of VL is emphasized even in non-endemic areas when monoclonal components in serum or urine specimens are found and consistent clinical findings are present.