Membranoproliferative glomerulonephritis (MPGN) can be secondary to infections, autoimmune diseases, or hematological disorders. MPGN is uncommon and has a poor renal prognosis. We report the case of a patient with a myelodysplastic syndrome, presenting with autoimmune inflammatory manifestations and rapidly progressing kidney failure. The kidney biopsy revealed MPGN with extracapillary proliferation. The patient's condition rapidly improved under corticosteroid therapy, with normalization of the kidney function. However, during corticosteroid treatment, the patient developed severe visceral leishmaniasis with cutaneous, splenic, and osteo-medullary involvement. Upon review, we found that parasites were already present in minimal quantities in the bone marrow biopsy performed three months prior to corticosteroid treatment. We cannot conclusively determine whether the kidney lesions are linked to the autoimmune inflammatory manifestations of the myelodysplastic syndrome or to leishmaniasis. This case may be noteworthy due to the combination of two diseases that could be responsible for the histological lesions, and emphasizes the importance of a thorough evaluation in the case of MPGN.