Nonislet Cell Tumor Hypoglycemia: A Rare Paraneoplastic Syndrome

Area of Science:

• Endocrinology
• Oncology
• Gastroenterology

Background:

• Nonislet cell tumor hypoglycemia (NICTH) is a rare cause of hypoglycemia, often linked to malignancies producing excessive insulin-like growth factor 2 (IGF-2).
• Diagnosis typically involves elevated IGF-2/IGF-1 ratios, with surgery as the primary treatment and glucocorticoids as an alternative.
• NICTH can be mistaken for more common causes of hypoglycemia, necessitating a thorough diagnostic approach.

Purpose of the Study:

• To present a unique case of NICTH in a young male with a gallbladder fossa mass.
• To highlight the diagnostic challenges and considerations for NICTH, especially when common causes are ruled out.
• To emphasize the importance of considering NICTH in patients with unexplained hypoglycemia and specific tumor markers.

Main Methods:

• Case report of a 27-year-old male with chronic hepatitis B, presenting with severe hypoglycemia.
• Diagnostic workup included assessment of insulin, C-peptide, IGF-1, IGF-2, and pituitary function.
• Immunohistochemical (IHC) analysis was performed on the gallbladder mass.

Main Results:

• The patient exhibited recurrent, severe hypoglycemia with suppressed insulin and C-peptide levels.
• Laboratory findings showed suppressed IGF-1 with a raised IGF-2/IGF-1 ratio, indicative of NICTH.
• A gallbladder fossa mass was identified as the likely source of IGF-2 overproduction.

Conclusions:

• This case underscores the importance of considering NICTH in the differential diagnosis of hypoglycemia, even in younger patients and with unusual tumor locations.
• Clinicians should suspect NICTH when standard hypoglycemia workup is inconclusive and IGF-2 levels are elevated.
• Prompt diagnosis and management, potentially involving surgery, are crucial for improving patient outcomes in NICTH.