Six months prior to admission, a 51-year-old man presented with indisposition, weakness and dark urine. Fifteen days earlier, he observed an increase in abdominal volume, a decrease in urinary volume, worsening macrohematuria, as well as lower limb edema and a 7-kg weight loss during the preceding year.
Approximately 15 months earlier, the patient presented with squamous-cell carcinoma of the mouth that was treated surgically. Subsequently, the patient received 35 sessions of radiotherapy. He had been a heavy smoker for 30 years but had stopped 3 years prior to these events; he had also been a moderate-to-severe alcoholic up to 3 years ago.
At the initial physical examination, the patient presented no signs of uremia. His blood pressure was 170/110 mm Hg, heart rate 76 b.p.m. and respiratory rate 16 breaths/min. He had a mitral systolic murmur. There was a cutaneous thickening in the cervical region, which had developed following radiotherapy, and his lymph nodes were not palpable. His abdomen was tense, with moderate ascites.
His initial laboratory blood tests tests showed: hemoglobin, 4.2 g/dl; platelets, 82,000/mm3; white blood cells, 5,600/mm3; prothrombin activity, 100%; iron, 90 mg/dl; ferritin, 243 μg/l; transferrin saturation, 39%; venous pH, 7.35; base excess, −7; creatinine, 583 μmol/l; urea, 51 mmol/l; glucose, 4.66 mmol/l; uric acid, 481.78 μmol/l; sodium, 139 mmol/l; potassium, 4.7 mmol/l; ionic calcium, 1.17 mmol/l; phosphorus, 3.10 mmol/l; lactic dehydrogenase, 41%; alkaline phosphatase, 50 U/l; prostate-specific antigen, 0.4 ng/ml; α-fetoprotein, 2.1 U/ml; IgG, 230 mg/dl; IgM, 16 mg/dl; IgA, 4,330 mg/dl (reference value: 68–423 mg/dl); creatinine clearance, 9 ml/min, and 24-hour proteinuria, 1.5 g/24 h. Urinalysis revealed proteinuria (2.8 g/l), 250,000 leukocytes/mm3 and 24 × 106 erythrocytes/mm3, with erythrocyte dysmorphism (3+); urine culture was negative. The urine Bence-Jones protein test was negative. The following serological tests were nonreactive: anti-HIV, anti-HCV, HbsAg, ANA, anti-DNA, anti-glomerular basement membrane (GBM) antibodies and ANCA. Serum complement levels were normal.
Ultrasonographically, the right and left kidney measured 12.1 × 6.8 × 3.5 and 12.0 × 5.2 × 4.6 cm, respectively, with an increase in echogenicity in the renal parenchyma suggesting chronic nephropathy.
Considering the possibility of rapidly progressive GN, he received single-dose methylprednisolone pulse therapy. He had an ultrasound-guided renal biopsy and was maintained on hemodialysis. Following biopsy, uncontrolled perirenal hemorrhage developed and he was then submitted to nephrectomy.
Light-microscopically, the renal biopsy revealed global sclerosis in 1 of 6 glomeruli; in the other glomeruli architecture was preserved: they were voluminous, hypercellular and exudative, with numerous polymorphonuclear leukocytes (fig. ). Using Masson's trichrome staining, some images were suggestive of ‘humps’, and the GBM presented areas of focal duplication; 50% of the renal cortex showed interstitial fibrosis and focal tubular atrophy, and discrete aggregates of lymphomononuclear cells presented concomitant with plasma cells. Immunofluorescence revealed a glomerular diffuse granular staining with anti-IgG, IgA, C3, and ĸ and λ light chains.
Thus, acute proliferative and exudative GN was diagnosed with evidence of tubulointerstitial disease and arteriolosclerosis.
Following nephrectomy, histopathological analysis of the left kidney revealed multifocal MM infiltration with the following findings: interstitial groups of well-differentiated neoplastic plasma cells; presence of a large number of intratubular hyaline casts; multifocal tubular dilatation, and diffuse endocapillary proliferative GN with fuchsinophilic subepithelial deposits, suggesting the presence of ‘humps’ (fig. ). No evidence of amyloid deposits was observed using Congo red staining. Renal biopsy showed 60% plasma cells, while a bone marrow biopsy revealed approximately 31% atypical plasma cells, confirming the diagnosis of MM.
The patient was then submitted to chemotherapy and maintained on dialysis. After 6 months, he died due to an infectious complication with no renal function improvement.
