Systemic lupus erythematosus and multiple myeloma: an uncommon association. Two cases and literature review.

The association of systemic lupus erythematosus and multiple myeloma is uncommon. We report two cases of systemic lupus erythematosus associated to multiple myeloma. The cases are discussed in the light of a review of the literature. The clinical, laboratory and radiographic findings of the patients, as well as the subsequent therapeutic approach are discussed. A systematic review of all the other cases of this association is performed. We report two female patients of 50 and 35 years old who developed a multiple myeloma seven and three years respectively after the diagnosis of systemic lupus erythematosus. In the second case, systemic lupus erythematosus was associated to monoclonal gammopathy. One patient died after three months and one patient is still in remission after three years of the diagnosis of multiple myeloma. The coexistence of systemic lupus erythematosus and multiple myeloma is very rare and the possible pathogenetic mechanisms underlying this association remain unclear.