Gastrointestinal stromal tumour

Gastrointestinal stromal tumour

Smooth muscle tumours of the rectum are rare. If the mitotic rate is high, and if there is variation in nuclear number, size and shape, hyperchromasia and frequent bizarre cells, these tumours are likely to metastasise. In these circumstances, they should be classified as malignant gastrointestinal stromal tumours (GISTs) (formerly leiomyosarcomas). The uncertainty in their behaviour means that treatment should, whenever possible, be radical excision.