A beta-hydroxytryptophan-secreting carcinoid tumour.

An atypical case of the malignant carcinoid syndrome, associated with multiple peptic ulcers, is described. The tumour cells were argyrophil but not argentaffin, and the tumour was found to contain 5-hydroxytryptophan (5-H.T.P.) but not 5-hydroxytryptamine (5-H.T.). This aberrant biochemical behaviour was associated with the virtual absence of 5-H.T.P.-decarboxylase from the tumour tissue. The tumour contained notable quantities of histamine.