Diagnostic performances of M-protein tests according to the clinical presentations of kidney disease.

BACKGROUND: Screening for monoclonal immunoglobulin (MIg) is critical in patients with kidney disease. METHODS: We identified 943 subjects who underwent kidney biopsy and at least one of monoclonal (M)-protein tests (serum and urine electrophoresis [EP], serum and urine immunofixation [IF], and serum free light chain [FLC] ratio). The sensitivities of several combinations of the 5 tests were examined by clinical presentations of kidney disease. RESULTS: The sensitivities of serum EP, urine EP, and the serum FLC ratio were 65%, 68%, and 71%, respectively, which were lower than those of serum IF (79%) and urine IF (87%) to detect MIg. In the nephrotic syndrome (NS) group, the panel including serum IF, urine IF, and the serum FLC ratio exhibited 100% sensitivity to identify MIg in patients with multiple myeloma (MM) or with monoclonal gammopathy of renal significance (MGRS). In subjects without NS, the panel of serum EP and serum FLC ratio detected MIg in all cases of MM, and the serum IF plus serum FLC ratio detected MIg in all cases of MGRS. CONCLUSION: This study demonstrated that the sensitivity of screening panels differed by the presenting features of kidney disease. The M-protein tests had lower sensitivity for detection of MIg in subjects with NS compared to those with other clinical presentation.

A case of Fanconi syndrome accompanied by crystal depositions in tubular cells in a patient with multiple myeloma.

Fanconi syndrome (FS) is a rare condition that is characterized by defects in the proximal tubular function. A 48-year-old woman was admitted for evaluation of proteinuria. The patient showed normal anion gap acidosis, normoglycemic glycosuria, hypophosphatemia, and hypouricemia. Thus, her condition was compatible with FS. The M peak was found behind the beta globulin region in urine protein electrophoresis. Upon bone marrow examination, we found that 24% of cells were CD138+ plasma cells with kappa restriction. From a kidney biopsy, we found crystalline inclusions within proximal tubular epithelial cells. Thereafter, she was diagnosed with FS accompanied by multiple myeloma. The patient received chemotherapy and autologous stem cell transplantation, and obtained very good partial hematologic response. However, proximal tubular dysfunction was persistent until 1 year after autologous stem cell transplantation. In short, we report a case of FS accompanied by multiple myeloma, demonstrating crystalline inclusion in proximal tubular cells on kidney biopsy.

Fibrous hamartoma of infancy: an experience of a single institute.

PURPOSE: Fibrous hamartoma (FH) of infancy is a distinctive fibrous growth that most frequently occurs at birth and during the postnatal period. It is important for clinicians and pathologists to recognize this entity to avoid an aggressive approach. METHODS: We herein describe the clinicopathologic features of 9 FHs diagnosed at a single institution between 1997 and 2010. RESULTS: There were 7 boys and 2 girls, and the mean age of presentation was 14.7 months. The common locations were the lower back and gluteal region (n = 3) and scrotum (n = 2). They were solitary lesions, and measured 1.0 to 7.0 cm in maximum diameter (mean, 4.9 cm). The excised masses tended to be poorly circumscribed, and consisted of an intimate mixture of firm, gray-white tissue with fat. Histologically, these lesions were composed of 3 components forming a vague, irregular, organoid pattern: well-defined intersecting trabeculae of fibrocollagenous tissue; loosely textured areas of small, rounded, primitive mesenchymal cells; and mature fat. Over a median follow-up of 72 months, no patient showed recurrence. CONCLUSION: FH should be distinguished from other forms of fibromatosis and malignant tumors because it is benign and usually cured by local excision.

Post-operative acute kidney injury in patients with renal cell carcinoma is a potent risk factor for new-onset chronic kidney disease after radical nephrectomy.

BACKGROUND: Radical nephrectomy is a significant risk factor for chronic kidney disease (CKD). There are few reports on the renal outcome of acute kidney injury (AKI) after radical nephrectomy. The aim of this study was to determine the incidence of AKI and whether post-operative AKI is associated with new-onset CKD after radical nephrectomy for renal cell cancer (RCC). METHODS: We conducted a retrospective study of 519 adult patients (>40 years old) with normal renal function who underwent unilateral radical nephrectomy for a solitary renal cortical tumour and were pathologically diagnosed with RCC between January 2000 and February 2007. Post-operative AKI was classed using risk, injury, failure, loss and end-stage kidney disease (RIFLE) criteria. CKD was defined as a decrease in estimated glomerular filtration rate (GFR) to <60 mL/min/1.73 m(2). RESULTS: According to the RIFLE criteria, 165 of 175 patients fell into the AKI risk category, 8 patients fell into the AKI injury category and 2 patients fell into the AKI failure category. Multivariate analysis revealed that older age [odds ratio (OR) 1.02, 95% confidence interval (CI) 1.00-1.05], male gender (OR 3.13, 95% CI 1.91-5.12), higher body mass index (OR 1.08, 95% CI 1.01-1.15), smaller RCC size (OR 0.87, 95% CI 0.81-0.93) and higher preoperative GFR (OR 1.04, 95% CI 1.03-1.06) were independent risk factors for post-operative AKI. CKD was more prevalent in the AKI risk group than in patients without AKI 1 year after surgery (54.7% versus 43.9%, respectively; P = 0.006) and 3 years after surgery (50% versus 32%, respectively; P = 0.003). Patients who experienced post-operative AKI had a 4.24-fold higher risk of new-onset CKD after multiple adjustments were made to the data (95% CI 2.28-7.89, P < 0.001). CONCLUSION: AKI after radical nephrectomy in patients with RCC is a potent risk factor for new-onset CKD. Prevention of post-operative AKI is essential for reducing the incidence of CKD after nephrectomy.