Metastasis in a benign duodenal stromal tumour.

Gastro-intestinal stromal tumour (GIST) is increasingly recognized as a distinct entity within the group of soft tissue tumours. Mostly, GIST arises from the muscular components of the stromal layer, but the tumour may also originate from the autonomic nerve system, recently designated as gastro-intestinal autonomic nerve tumour (GANT). The majority of GIST is located in the stomach and small intestine; only 4% of GIST is found in the duodenum. Clinical and pathological criteria to differentiate benign from malignant GIST are not well established. Tumour size and mitotic activity are commonly considered as important features, predicting biological behaviour and outcome. It has been suggested that the clinical course of the GANT-type tumours may be more aggressive. We present a case of a radically resected duodenal stromal tumour with benign features, in a young woman, with metastases to the liver and peritoneum occurring 8 years after the initial diagnosis.