Abstract
Patients on long term lithium therapy for affective disorders may develop renal toxicity. It may manifest as nephrogenic diabetes insipidus with renal biopsy showing interstitial fibrosis, sclerotic glomeruli and cyst formation. Magnetic resonance imaging demonstrates the presence of microcysts in patients on long-term lithium therapy, suggesting a possible cause for their nephrotoxicity. We describe the typical magnetic resonance imaging appearance of renal microcysts in a 53 year old woman on chronic lithium therapy.