Congenital gastrointestinal stromal tumour is morphologically indistinguishable from the adult form, but does not express CD117 and carries a favourable prognosis

Aims: The histological and immunohistochemical features of a congenital str omal tumour of the jejunum are compared with those of adult gastrointestina l stromal tumours (GIST). The literature concerning the diagnosis and progn osis of congenital small intestinal stromal tumours is reviewed. Methods and results: A term female infant presented with intestinal obstruc tion, from birth. Histology of a 15-mm jejunal nodule showed a predominantl y spindle-cell tumour with epithelioid areas. There was a low mitotic count and mild nuclear pleomorphism, extensive necrosis and haemorrhage, and foc al calcification. Immunohistochemically, tumour cells stained for muscle sp ecific actin and vimentin, Staining for CD117 (c-kit). S100, desmin and CD3 4 was negative. The features were compared to those of seven adult cases: n o morphological feature was specific to the congenital tumour, which was sm aller than the adult cases. There were no ultrastructural features specific for a particular line of differentiation, Immunohistochemical staining pat terns were similar, except for CD117, which was strongly positive in all ad ult rumours, but negative in the congenital tumour. Conclusions: This congenital jejunal stromal tumour morphologically resembl ed adult GIST, but lack of c-kit expression suggests that it is nosological ly distinct. Despite the presence of histological features which would caus e the tumour to be categorized as malignant in an adult, it is apparent fro m previous reports of congenital small intestinal stromal tumours that the prognosis is favourable.