Corticosteroids and Mycophenolate Mofetil are used more often in the treatment of C3 glomerulopathies, which are rare subtypes of Idiopathic Membranoproliferative Glomerulonephritis. Immunosuppressive therapies used in the treatment of such glomerular diseases may be a trigger for the activation of latent tuberculosis infections. Although it is not recommended routinely in the guidelines, a routine evaluation for latent tuberculosis would be appropriate both before starting immunosuppressive treatments and during the investigation of secondary causes, especially in countries where tuberculosis infection is common. We aimed to draw attention to this issue by presenting a case of miliary tuberculosis and synchronous central nervous system lymphoma developing secondary to Corticosteroid and Mycophenolate Mofetil treatment with the diagnosis of C3 nephritis.