Cholesterol granuloma of the kidney mimicking a tumour

Gowreeson Thevendran1, Mahmoud Al-Akraa1, Stephen Powis1 and Neil Davies2

1Department of Renal Transplant and 2Department of Radiology, Royal Free Hospital, London, UK

Correspondence and offprint requests to: Gowreeson Thevendran, Department of Renal Transplant, Royal Free Hospital, London, UK. Email: xanthus23{at}hotmail.com

Keywords: cholesterol emboli; cholesterol granuloma; kidney

Introduction

Cholesterol granulomas are lesions consisting of cholesterol crystals and foreign body giant cells [1]. Lipid disturbances are thought to play a role in their aetiology. They are rare histological diagnoses in renal lesions. This case appears to be the first reported in the English literature of a cholesterol granuloma of the kidney mimicking a tumour.

Case report

A 67-year-old woman was investigated for hypertension and dipstick haematuria. A renal ultrasound scan demonstrated a normal right kidney and a left renal mass. Enhanced computed tomography (CT) confirmed the presence of a 3 cm solid mass, highly suggestive of malignancy. The mass arose from the anterior limb of the upper pole of the left kidney and extended beyond the capsule (Figure 1). A subsequent magnetic resonance angiogram (MRA) scan further highlighted diffuse atheroma and stenosis at the origin of the left renal artery.



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Fig. 1. CT scan of the mass in the left kidney.

 
In view of left renal artery stenosis and a high index of suspicion of malignancy, a left radical nephrectomy was performed. Subsequent histological examination (Figure 2) demonstrated a multicystic mass, containing florid cholesterol granulomas and fibrosis. No evidence of malignancy was seen.



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Fig. 2. Histological examination of the mass.

 
Discussion

A study of patients with nephrotic syndrome suggested that renal tubular cholesterol crystals are not infrequent manifestations of the lipid abnormalities of serum and urine in nephrotic syndrome [2]. Though the patient in our case was not nephrotic, she was known to be hypercholesterolaemic and had an atheromatous left renal artery. Thus it may seem possible that cholesterol embolization is partly to blame. In conclusion, detection of a renal mass in hypercholesterolaemic and atherosclerotic patients does not necessarily imply a presumptive diagnosis of renal cell carcinoma, and perhaps further assessment with a positron emission tomography (PET) scan or a pre-operative needle biopsy may help avoid an unnecessary nephrectomy.

Conflict of interest statement. None declared.

References

  1. Lowenthal SB, Goldstein AMB, Terry R. Cholesterol granuloma of tunica vaginalis simulating testicular tumour. Urology 1981; 18: 89–90[ISI][Medline]
  2. Nast CC, Cohen AH. Renal cholesterol granulomas: identification and morphological pattern of development. Histopathology 1985; 9: 1195–1204[ISI][Medline]