Studies on the mechanism of hypoglycemia in a patient with massive intraperitoneal leiomyosarcoma

Abstract

A patient with severe hypoglycemia in association with massive intra-abdominal metastasis from a gastric leiomyosarcoma is described. The results of glucose tolerance tests showed rapid decrease of blood sugar after administration of glucose. Suboptimal response of the blood glucose to glucagon and epinephrine, as well as direct tissue measurements of glycogen and glucose in tumor, liver and muscle, indicated that the patient had diminished glycogen reserves. The fall in blood sugar levels after tolbutamide was administered was not of the degree which occurs in patients with insulin-producing, tolbutamide-sensitive tumors. To maintain normoglycemia it was necessary to infuse glucose at a rate of 12 mg. per kg. per minute. During glucose infusion, or following glucose injection, an exceptional increase in venous lactate occurred which was greater in blood draining the tumor than in that of an extremity vein. Excess lactate during hypoglycemia was calculated to be present, but disappeared transiently as blood pyruvate and glucose levels rose. There was no significant evidence of increased tryptophan metabolites. Serum insulin levels on one occasion were normal. Assay of an acid-alcohol tumor extract indicated the presence of 0.005 units per gm. of insulin by immunoassay and 0.04 units per gm. of insulin-like activity by fat pad assay. The data support the conclusion that excessive utilization of glucose by the massive neoplasm led to hypoglycemia. Such utilization may have been dependent in part upon insulin or on insulin-like substances present in the tumor.