Long-term clinical course of immunotactoid glomerulopathy complicated with diffuse large B-cell lymphoma

We report a case of immunotactoid glomerulopathy (ITG) complicated with diffuse large B-cell lymphoma (DLBCL). A 68-year-old woman presented with leg edema and was diagnosed with nephrotic syndrome (NS). Renal biopsy revealed ITG. We treated the patient with prednisolone (20 mg/day) and she achieved complete remission of NS. Steroids were gradually reduced. After 1 year, the patient presented with a breast mass determined on biopsy to be DLBCL. She underwent six cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) therapy. Follow-up revealed complete remission of both DLBCL and ITG. NS recurred after 5 years and she was simultaneously diagnosed with recurrence of DLBCL in bone marrow. She underwent four cycles of R-EPOCH (rituximab, etoposide, prednisolone, vincristine, cyclophosphamide, doxorubicin) therapy and entered remission for DLBCL. NS improved, but the treatment did not lead to remission. After 2 additional years, NS and DLBCL recurred again. She was administered rituximab and NS improved, although proteinuria tended to increase thereafter. One year later, we started prednisolone (10 mg/day), and proteinuria tended to decrease. She is currently undergoing outpatient follow-up. This case suggests that ITG with MGUS should be treated with the possibility of developing malignant hematological disease during the course.