Neurofibromatosis associated with somatostatinoma: a report of two patients.

Two patients with neurofibromatosis and somatostatinoma are described, one patient in addition having a parathyroid adenoma diagnosed post mortem. The other patient had a partial somatostatinoma syndrome with diabetes, abdominal pain and cholelithiasis. The tumour was diagnosed preoperatively and metabolic studies demonstrated mild diabetes mellitus apparently due to suppression of insulin secretion by somatostatin, since oral glucose tolerance returned to normal post-operatively despite hemipancreatectomy. The tumour also secreted gastrin. There are now 18 reported cases of neurofibromatosis and duodenal carcinoid tumours which makes a genuine association between these two conditions very likely. With the present two cases, seven of the carcinoid tumours in this group have been positively identified as somatostatinomas. The histological finding of psammoma bodies is important in the diagnosis of duodenal somatostatinomas.