A 50-year-old Caucasian male with a history of alcohol and injection-drug abuse, chronic HCV infection, coronary heart disease, and idiopathic renal function impairment (creatinine clearance < 60 mL/min) for preceding four months attended in the emergency department with uremic symptomatology. He was dysphonic (O2 saturation, 85%) and hypertensive (blood pressure, 185/90 mmHg) and had prominent hepatosplenomegaly with mild peripheral edema; he had no palpable lymph nodes, skin rash, or other manifestations of systemic diseases. Laboratory analyses results were as follows: metabolic acidosis (pH, 7.123; and HCO3-, 8.6 mmol/L); mild hyperkalemia (K+, 5.7 mmol/L); hyperphosphatemia (PO43-, 10 mg/dL); hypoalbuminemia (albumin, 2.8g/L); anemia (hematocrit, 21.2%; and hemoglobin, 6.8 g/dL); thrombocytopenia (platelet, 72 × 10³/μL); lactate dehydrogenase,185 U/L; and severe renal failure (serum creatinine, 9.9 mg/dL; and urea, 199 mg/dL) with signs of glomerular involvement (urine red blood cells, 40 to 60/HPF; and 24-hour urine proteins, 3.06 g).\nThe clinical and laboratory findings on admission necessitated the immediate start of hemodialysis. Subsequent ultrasound studies revealed hepatosplenomegaly, two kidneys of normal size (right kidney, 11.7 cm; and left kidney, 11.5 cm), and parenchymal thickness (right kidney, 10 mm; and left kidney, 9.9 mm). There was no clinical or radiological sign of lymph nodes involvement. Further laboratory testing by immunological assay (ANA, anti-dsDNA, ASMA, AMA, C-ANCA, P-ANCA, and C3 complement levels) had negative results except for serum proteins electrophoresis, which showed a monoclonal gammopathy of IgM. At the same time, urine immunofixation revealed the presence of albumin, IgM, and kappa light chains, type I cryoglobulinemia, and low C4 complement levels. Considering the history of the patient and after excluding and treating all other causes of renal function deterioration, our diagnostic approach pointed towards an HCV-related renal offence in the context of cryoglobulinemia. However, the rapid decline of renal function and the absence of mixed cryoglobulinemia suggested performing the renal biopsy. While the histopathological examination of the specimen was consistent with the initial suspicion, indicating MPGN (), the immunofluorescence study revealed two unusual findings: dominant monoclonal IgMκ deposits in glomerular basement membrane and infiltration of the interstitium by abundant strongly IgM-positive lymphoid cells (). The presence of CD20 cell marker was distinctive while CD5 was absent. According to these findings, a bone marrow biopsy was performed. The histopathological examination revealed plasmacytic differentiation of small B cells and the immunophenotyping results were positive for CD20 and negative for CD5. These findings were consistent with SMZL. The patient became hemodialysis dependent and received no treatment for the lymphoproliferative disease and was monitored regularly for possible transformation to a high-differentiated lymphoma.
A 19-year-old male patient was admitted to the Nephrology Department of Ankara University Faculty of Medicine due to painless hematuria, bilateral renal masses, and acute kidney injury for further investigations. He was first evaluated at another center for hematuria. There was one episode of hematuria, which had subsided spontaneously. Abdominal ultrasonography had revealed bilateral diffuse renal masses and the patient was referred to our center for further examination.\nOn admission, there was no history of fever, weight loss, night ssweats and any other health problem. The patient’s physical examination findings were unremarkable. In particular, there was no peripheral lymphadenopathy or hepatosplenomegaly. Also the kidneys were not palpable. Laboratory tests revealed white blood cell count of 7.7x109/L, hemoglobin of 11.6 g/dL, platelet count of 315x109/L, serum blood urea nitrogen of 17 mg/dL, serum creatinine of 1.5 mg/dL (normal range: 0.5-0.9), serum uric acid of 7.6 mg/dL (normal range: 2.4-5.7), serum lactate dehydrogenase of 1042 U/L (normal range: 125-220), and serum ferritin of 749 ng/mL (normal range: 11-307). Erythrocyte sedimentation rate was 52 mm/h and C-reactive protein level was 27.5 mg/L (normal: <3). Urinalysis showed density of 1010, pH of 5.5, protein of 15 mg/dL, and glucose negative, and urine microscopy showed 4 leukocytes and 3 erythrocytes per high-power field. Viral serology tests were negative. C3 and C4 as well as quantitative immunoglobulin levels were all within normal limits with negative antinuclear antibody and anti-neutrophil cytoplasmic antibody tests. Urinary ultrasonography demonstrated bilaterally enlarged kidneys without obstruction (right: 16x8 cm, left: 15.5x8 cm) and numerous solid hypoechoic nodular cortical masses in both kidneys (largest of 6.5x5.5 cm in size, numerous variably sized masses) with perirenal and paraaortic multiple enlarged lymph nodes (largest <2.5 cm in size).\nContrast-enhanced computerized tomography (CT) scanning of the abdomen confirmed bilaterally enlarged kidneys, bilateral variably sized multiple hypodense renal masses, and paraaortic, paracaval multiple enlarged lymph nodes (). In addition, the liver was slightly enlarged with normal parenchyma while the size of the spleen and parenchyma was normal.\nThereafter, 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) was performed for staging and its role in the differential diagnosis. It was performed to examine the entire body, revealing an abnormal accumulation in the thyroid gland, anterior mediastinum, bilateral hilar, right parasternal lymph node, left subdiaphragmatic lymph node, bilateral renal cortices, and multiple abdominal paraaortic, paracaval, and aortocaval lymph nodes ( and ).\nA percutaneous tru-cut biopsy of the kidney was performed and histopathological examination showed extensive infiltration of the renal parenchyma by atypical lymphoid cells ( and ). Immunohistochemical studies demonstrated positive staining of the neoplastic cells for CD20, CD10, bcl-6 (, , , and ) and negative results for MUM1 () and Bcl-2. The ki-67 proliferation index of neoplastic cells was 80% (). EBER in situ hybridization was negative. A diagnosis of diffuse large B-cell non-Hodgkin lymphoma (NHL) was made. To exclude lymphoma involvement of the bone marrow, the patient underwent bone marrow biopsy and there was not bone marrow infiltration.\nSubsequently, the patient was transferred to the department of hematology for treatment and chemotherapy regimen as well; cyclophosphamide, adriamycin, vincristine, prednisolone, and rituximab (CHOP+R) were started. After a cycle of chemotherapy, the patient’s renal functions returned to normal.