Cystic lesions of the kidney—selected topics

This article outlines a number of cystic lesions that may either cause diagnostic problems or in which there has been recent interest. The pathologist is usually faced with solitary cystic lesions following a radical or partial nephrectomy for a suspected tumour. Diagnosis can rarely be made preoperatively, however, some occur almost exclusively in infants and children while others are found in older age groups. The paediatric cystic tumours present as symptomless masses or incidental findings following radiological examination. Preoperative diagnosis is difficult and such a lesion would usually be subject to a radical nephrectomy. Precise histological diagnosis is important as some may be cystic variants of malignant tumours that will require further treatment. In contrast, adult solitary cystic lesions are usually treated by surgery only. The significance of pathological examination here is accurate diagnosis to assess prognosis. Descriptions of the renal lesions in von Hippel–Lindau disease and acquired cystic disease are included as there have been recent developments in both and pathologists may see resections from these patients with increasing frequency.