The Case ∣ Full moon and new moon

The Case ∣ Full moon and new moon

make your diagnosis http://www.kidney-international.org & 2008 International Society of Nephrology Kidney International (2008) 73, 515–516; doi:10.10...

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make your diagnosis

http://www.kidney-international.org & 2008 International Society of Nephrology Kidney International (2008) 73, 515–516; doi:10.1038/sj.ki.5002733

The Case | Full moon and new moon K-L Liu1, S-C Chueh2, W-J Lee1, K-H Huang2 and S-J Chen1 1

Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan and 2Department of Urology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan Correspondence: S-J Chen, Department of Medical Imaging, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 100, Taiwan. E-mail: [email protected]

Figure 1 | Milk of calcium in supine abdominal radiograph. Supine abdominal radiograph shows two radiopaque masses consisting of numerous ‘pearls’. The superior one (arrow) is located at the renal cortical area but the inferior one (arrowhead) is out of renal contour due to an exophytic renal cyst.

Figure 2 | Milk of calcium in standing abdominal radiograph. Typical crescent shapes of milk of calcium are identified in the standing film due to a fluid–fluid level, with precipitation of milk of calcium in the dependent portion.

A 72-year-old man was admitted with a diagnosis of cryptogenic organizing pneumonia. He also complained of abdominal discomfort at the epigastric area, with soft abdomen and without tenderness or peritoneal sign. A blood sampling showed leukocytosis 13 930 ml 1, urea

nitrogen 29.3 mg per 100 ml (normal 4.5–24), and creatinine 1.6 mg per 100 ml (normal 0.6–1.3). The urinalysis did not disclose abnormal findings. Supine and upright abdominal radiographs were performed (Figures 1 and 2) for workup of his abdominal discomfort.

What is the clinical diagnosis?

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make your diagnosis

K-L Liu et al.: Full moon and new moon

The Diagnosis | Milk of calcium in renal cysts

Figure 3 | Milk of calcium in supine abdominal computed tomography scan. Milk of calcium precipitates in the dependent areas of the cysts, forming the layering opacification in the standing abdominal radiograph.

DISCUSSION

Abdominal plain films revealed two radiopaque masses in the right upper quadrant. Each mass consisted of numerous nodules, like a cluster of small pearls. The superior mass (arrow, Figure 1) was located at the renal cortical area, but the inferior one lay outside the renal shadow (arrowhead, Figure 1). An upright radiograph was taken and showed the typical crescent shapes of fluid–fluid levels (Figure 2). Milk of calcium in the renal cysts was diagnosed due to the typical crescent shapes of layering opacification (fluid–fluid level) in the standing film (Figure 2). These two lesions were also confirmed by previous computed tomography scan for the lung lesions at his admission (Figure 3). Milk of calcium is a colloid suspension of precipitated calcium salts such as calcium oxalate monohydrate or phosphate, and mimics a renal calculus. Pathogenesis is unknown. Possible contributing factors include stasis, urinary tract infection, or long-term immobility. Typical features on supine plain radiographs are numerous calcified

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‘pearls’ assuming a crescent shape in upright films, as in this case. Hyperechoic material and a sharp horizontal level can be visualized using ultrasound. In symptomatic patients, the traditional open surgical techniques have been replaced with percutaneous endourological marsupialization of renal cysts,1 with closure of caliceal infundibulum in cases of caliceal diverticulum. The majority of patients do not exhibit symptoms. Recognition and correct diagnosis can avoid surgical intervention or unwarranted lithotripsy.2 In this patient, the milk of calcium in the renal cysts was incidentally found. The urinalysis did not reveal hematuria and the patient was clinically followed without further investigation or need for intervention. REFERENCES 1.

2.

Kikuchi E, Sumitomo M, Hatakeyama N, Baba S, Murai M. Percutaneous endoscopic marsupialization of a pyelocaliceal diverticulum with milk of calcium stones. Urol Int 1998; 60: 62–65. Heidenreich A, Vorreuther R, Krug B, Moul JW, Engelmann UH. Renal milk of calcium: contraindication to extracorporeal shockwave lithotripsy. Tech Urol 1996; 2: 102–107.

Kidney International (2008) 73, 515–516