Presacral carcinoid tumour arising in a tailgut cyst--a case report.

Primary carcinoid tumours of the presacral region are extremely infrequent with just a handful of such cases reported in literature. Tailgut cysts(retrorectal cystic hamartoma) are also very uncommon lesions which are usually identified in adult life. They are developmental abnormalities and consist of multiloculated cysts lined by squamous, transitional or glandular epithelium. Malignant transformation within tailgut cysts is rare; the tumours which arise include carcinoid tumours and adenocarcinomas. We report the unusual occurrence of a carcinoid tumour developing within a tailgut cyst.