Objective : Report a case of nonislet cell tumor causing persistent hypoglycemia that resolved with surgical intervention.
We present a 83-year-old woman with type 2 diabetes mellitus and uterine leiomyoma who presented to the ER with rectal bleed prior to scheduled hysterectomy. Patient reported using glipizide, which was discontinued 3 weeks prior due to hypoglycemia. Admission labs notable for Na 148, K 3.1; no renal or hepatic dysfunction, albumin 2.7. HgA1c 4.5%, Cortisol 8.6, ACTH 10 and TSH 1. Cosyntropin stimulation test showed cortisol 21.7 at 60 minutes.
Patient underwent 72-hour fasting after Whipple triad was documented. She developed symptomatic hypoglycemia after 6 hours; glucose 42mg/dl, C-peptide 0.43, pro insulin 25 mg/dL. Beta-hydroxybutyrate <1.0. Abdominal imaging showed fibrous uterus and focal thickening within ascending colon. Colonoscopy revealed tubular adenoma with dysplasia in ascending colon. Patient had profound hypoglcemia despite treatment with 10% dextrose infusion, tube feeding and glucocorticoids.
The clinical, laboratory and radiological evaluation increased the index of suspicion for NICTH. IGF1 and IGF2 were ordered. IGF1: 21 and IGF2: 249; IGF2 to IGF1 ratio: 10.82. Patient underwent hysterectomy and small tumor bowel resection. Surgical pathology showed pelvic gastrointestinal stromal tumor. After resection, hypoglycemia resolved. Dextrose and steroids were tapered with resolution of hypoglycemia.
NICTH is a rare but serious paraneoplastic process of tumoral overproduction of IGF2. An IGF-2 to IGF-1 ratio above 10 strongly suggests the diagnosis. The therapeutic approach in NICTH involves complete removal of the tumor if possible. Enteral or parenteral feeding, glucagon (if glucagon responsive), and growth hormone are alternative therapies. This case illustrates an uncommon cause of severe hypoglycemia associated with GIST with complete resolution after surgical resection.
Carlos Pla Fernandez– Endocrinology fellow, University of South Florida, Tampa, Florida
Vindya Gunawardena– Fellow, University of South Florida
Marla Sevilla– Attending, University of South Florida
Joaquin Gomez-Daspet– Program director, University of South Florida
University of South Florida