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Massive bilateral nephromegaly in an infant
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http://www.kidney-international.org & 2012 International Society of Nephrology
Kidney International (2012) 82, 828; doi:10.1038/ki.2012.134
Massive bilateral nephromegaly in an infant Catalina Franco-Alzate1, Maria C. Prada2 and Luis F. Arias1 1
PRYT Group, Department of Pathology, Faculty of Medicine, University of Antioquia, Medellı´n, Colombia and 2Department of Pediatric Nephrology, Hospital Universitario San Vicente Fundacio´n, Medellı´n, Colombia Correspondence: Luis F. Arias, PRYT Group, Department of Pathology, Faculty of Medicine, University of Antioquia, Carrera 51D No. 62-29, Medellı´n, Colombia. E-mail: [email protected] or [email protected]
Figure 1 | Bilateral and massive enlargement of the kidneys, occupying almost the entire transverse diameter of the abdomen.
Figure 2 | Kidney parenchyma with dense infiltration by histiocytes, which entrap tubules and have cytoplasmic rounded structures: the Michaelis–Gutmann bodies (arrows). Periodic acid-Schiff staining, original magnification 400.
A 5-month-old girl presented with symptoms of malnutrition and severe urinary tract infection, with signs of sepsis and acute renal failure: serum creatinine, 1.4 mg/dl. Both blood and urine cultures were positive for Escherichia coli, and antibiotic therapy was started. Severe, almost symmetrical, bilateral nephromegaly was evident on computed tomography (Figure 1). Voiding cystourethrography showed no urinary tract abnormalities. Bilateral renal biopsies were performed and bilateral malakoplakia was diagnosed. Malakoplakia is the result of a defect in macrophage function, causing impairment of bactericidal activity. The large macrophages that are present at sites of infection (von Hansemann cells) exhibit numerous secondary lysosomes containing partially digested organisms. Calcification of these lysosomes
results in the formation of intracytoplasmic bodies called Michaelis–Gutmann bodies (Figure 2), considered pathognomonic of the disease. Renal parenchymal involvement may produce varying degrees of renal enlargement. Other relatively frequent described causes of massive bilateral non-cystic nephromegaly include renal infiltration by hematolymphoid diseases, nephroblastomatosis, megalocystic interstitial nephritis, xanthogranulomatous pyelonephritis, and other infections. At 6 months after diagnosis, the patient is well, but nephromegaly continues and her serum creatinine level is 0.7 mg/dl (creatinine clearance 33 ml/min). Prognosis of renal malakoplakia in children is variable: some patients recover completely, others develop end-stage renal disease, and others may die.
828
Kidney International (2012) 82, 828
http://www.kidney-international.org & 2012 International Society of Nephrology
Kidney International (2012) 82, 828; doi:10.1038/ki.2012.134
Massive bilateral nephromegaly in an infant Catalina Franco-Alzate1, Maria C. Prada2 and Luis F. Arias1 1
PRYT Group, Department of Pathology, Faculty of Medicine, University of Antioquia, Medellı´n, Colombia and 2Department of Pediatric Nephrology, Hospital Universitario San Vicente Fundacio´n, Medellı´n, Colombia Correspondence: Luis F. Arias, PRYT Group, Department of Pathology, Faculty of Medicine, University of Antioquia, Carrera 51D No. 62-29, Medellı´n, Colombia. E-mail: [email protected] or [email protected]
Figure 1 | Bilateral and massive enlargement of the kidneys, occupying almost the entire transverse diameter of the abdomen.
Figure 2 | Kidney parenchyma with dense infiltration by histiocytes, which entrap tubules and have cytoplasmic rounded structures: the Michaelis–Gutmann bodies (arrows). Periodic acid-Schiff staining, original magnification 400.
A 5-month-old girl presented with symptoms of malnutrition and severe urinary tract infection, with signs of sepsis and acute renal failure: serum creatinine, 1.4 mg/dl. Both blood and urine cultures were positive for Escherichia coli, and antibiotic therapy was started. Severe, almost symmetrical, bilateral nephromegaly was evident on computed tomography (Figure 1). Voiding cystourethrography showed no urinary tract abnormalities. Bilateral renal biopsies were performed and bilateral malakoplakia was diagnosed. Malakoplakia is the result of a defect in macrophage function, causing impairment of bactericidal activity. The large macrophages that are present at sites of infection (von Hansemann cells) exhibit numerous secondary lysosomes containing partially digested organisms. Calcification of these lysosomes
results in the formation of intracytoplasmic bodies called Michaelis–Gutmann bodies (Figure 2), considered pathognomonic of the disease. Renal parenchymal involvement may produce varying degrees of renal enlargement. Other relatively frequent described causes of massive bilateral non-cystic nephromegaly include renal infiltration by hematolymphoid diseases, nephroblastomatosis, megalocystic interstitial nephritis, xanthogranulomatous pyelonephritis, and other infections. At 6 months after diagnosis, the patient is well, but nephromegaly continues and her serum creatinine level is 0.7 mg/dl (creatinine clearance 33 ml/min). Prognosis of renal malakoplakia in children is variable: some patients recover completely, others develop end-stage renal disease, and others may die.
828
Kidney International (2012) 82, 828