Angiomyolipoma of the Kidney: The Experience at the University Hospital of the West Indies

Angiomyolipoma (AML) of the kidney is an uncommon tumour that, until recently, was often misdiagnosed preoperatively as renal cell carcinoma (RCC). Newer radiological techniques have allowed more accurate preoperative diagnosis which can facilitate preoperative counselling and planning for conservative therapy. This study reviews the experience with these uncommon tumours at the University Hospital of the West Indies. All cases of AML diagnosed during the period 1980 to 2007 were retrospectively identified from the files of the Department of Pathology. From these records, selected data were retrieved and analysed. These included patient demographics, clinical history, clinical diagnosis and pathologic characteristics of the specimen submitted. The total number of primary renal tumours diagnosed in adults during the same period was also determined for comparison. Eleven cases of AML were identified among 149 primary renal tumours in adults. Ten of these cases occurred in women. Amongst these, a single case of tuberous sclerosis was confirmed in a patient with bilateral lesions. Excluding this patient, who was 24-years-old, ages ranged from 24 to 86 years with a mean of 44 years (median 40.5 years) and an equal number of lesions was present on each side. Abdominal or flank pain were the most common clinical symptoms, present in six cases but in three cases, the tumours were discovered incidentally. The correct clinical diagnosis was made pre-operatively in a single case. By contrast, a diagnosis of RCC or other malignant tumour was proffered in eight cases. Pathologically, the maximum dimension of the seven excised tumours, in whom such information was recorded, ranged from 3.5 cm to 12 cm with a median of 7 cm. Spontaneous haemorrhage in the tumour was noted in three cases, all greater than 4.5 cm in maximum dimension. These data confirm that AML is uncommon at the University Hospital of the West Indies. There was an overwhelming female preponderance and patients presented, most commonly, in the 3rd to 4th decades. Tuberous sclerosis was identified in a solitary case. In this series, symptomatic lesions were > 4.5 cm in maximum dimension and haemorrhage complicated three cases. Most cases were incorrectly diagnosed preoperatively.