Background Kidney diseases associated with immunoglobulin M (IgM) monoclonal gammopathy are poorly described, with few data for patient outcomes and renal response. Study Design Case series. Setting ...& Participants 35 patients from 8 French departments of nephrology were retrospectively studied. Inclusion criteria were: (1) detectable serum monoclonal IgM, (2) estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 and/or proteinuria with protein excretion > 0.5 g/d and/or microscopic hematuria, and (3) kidney biopsy showing monoclonal immunoglobulin deposits and/or lymphomatous B-cell renal infiltration. All patients received chemotherapy, including rituximab-based regimens in 8 cases. Predictors Patients were classified into 3 groups according to renal pathology: glomerular AL amyloidosis (group 1; n = 11), nonamyloid glomerulopathies (group 2; n = 15, including 9 patients with membranoproliferative glomerulonephritis), and tubulointerstitial nephropathies (group 3; n = 9, including cast nephropathy in 5, light-chain Fanconi syndrome in 3, and isolated tumor infiltration in 1). Outcomes Posttreatment hematologic response (≥50% reduction in serum monoclonal IgM and/or free light chain level) and renal response (≥50% reduction in 24-hour proteinuria or eGFR ≥ 30 mL/min/1.73 m2 in patients with glomerular and tubulointerstitial disorders, respectively). Results Nephrotic syndrome was observed in 11 and 6 patients in groups 1 and 2, respectively. Patients in group 3 presented with acute kidney injury (n = 7) and/or proximal tubular dysfunction (n = 3). Waldenström macroglobulinemia was present in 26 patients (8, 12, and 6 in groups 1, 2, and 3, respectively). Significant lymphomatous interstitial infiltration was observed in 18 patients (4, 9, and 5 patients, respectively). Only 9 of 29 evaluable patients had systemic signs of symptomatic hematologic disease (2, 5, and 2, respectively). In groups 1, 2, and 3, respectively, hematologic response was achieved after first-line treatment in 3 of 9, 9 of 10, and 5 of 6 evaluable patients, while renal response occurred in 5 of 10, 9 of 15, and 5 of 8 evaluable patients. Limitations Retrospective study; insufficient population to establish the impact of chemotherapy. Conclusions IgM monoclonal gammopathy is associated with a wide spectrum of renal manifestations, with an under-recognized frequency of tubulointerstitial disorders.
Abstract Mesonephric remnant (MR) hyperplasia in the prostate is a rarely reported condition that is usually distinguished from prostatic adenocarcinoma by the absence of cytologic atypia as well as ...the absence of prostatic markers (prostate-specific antigen and prostatic acid phosphatase) expression. We report a case of prostatic MR hyperplasia with architectural and cytologic atypia in a 56-year-old man. The microscopic appearance strongly suggested malignancy, but immunohistochemistry allowed the diagnosis to be corrected. The presence of MRs in prostate tissues may be more common than appreciated or reported. Once the possibility is considered, the diagnosis is easily confirmed using immunochemistry.
