Endocrine Abstracts

A 75 year old woman was treated for over three years with the somatostatin analogue, octreotide for insulinoma. She had presented in a hypoglycaemic coma. C-peptide and insulin levels were both raised. Cortisol, TSH, a gut hormone screen and urinary sulphonylurea levels were all normal. No adenoma was identified on CT or MRI scanning but angiography showed an area of increased vascularity within the pancreas. At laparotomy no lesion was found and no resection was undertaken. Biopsies from the pancreas and local lymph nodes were histologically normal. A repeat CT scan, 36 months later showed no evidence of insulinoma. 43 months from starting octreotide, it was stopped. Repeat measurements of glucose and insulin were in the normal range; the C-peptide level was just above it. Alteration of the hormone environment has caused a reduction in size in other endocrine tumours, for example, prolactinomas, when treated with bromocriptine (Wass et al.,1982, George et al., 1979) and VIPomas when treated with octreotide (Kraenzlin et al.,1983, Kraenzlin et al., 1985). Although there is no imaging evidence of a reduction in size of the tumour, the persistently lower levels of insulin after withdrawal of octreotide could only be accounted for by a reduction in the functional size of the tumour.

References

George,S.R., Burrow,G.N., Zinman,B. & Ezrin,C. (1979) Regression of pituitary tumours, a possible effect of bromergocryptine. The American Journal of Medicine, 66, 697-702.

Kraenzlin,M.E., Ch'ng,J.C., Wood,S.M. & Bloom,S.R. (1983) Can inhibition of hormone secretion be associated with endocrine tumour shrinkage? The Lancet, 31, 1501

Kraenzlin,M.E., Ch'ng,J.L., Wood,S.M., Carr,D.H. & Bloom,S.R. (1985) Long term treatment of a VIPoma with somatostatin analogue resulting in remission of symptoms and possible shrinkage of metastases. Gastroenterology, 88, 185-187.

Wass,J.A.H., Williams,J., Charlesworth,M., Kingsley,D.P.E., Halliday,A.M., Doniach,I., Rees,L.H., Mcdonald,W.I. & Besser,G.M. (1982) Bromocriptine in management of large pituitary tumours. British Medical Journal, 284, 1908-1911