Insulinoma With Concomitant Insulin Antibodies

Area of Science:

• Endocrinology
• Oncology
• Immunology

Background:

• Insulinoma, a rare pancreatic neuroendocrine tumor, typically presents with hypoglycemia.
• Insulin antibodies are usually associated with exogenous insulin use or autoimmune conditions.
• The simultaneous occurrence of insulinoma and insulin antibodies is exceptionally rare.

Observation:

• A patient presented with severe symptomatic hypoglycemia and was diagnosed with insulinoma.
• Laboratory tests revealed elevated insulin and proinsulin levels with a low insulin-to-C-peptide ratio, indicative of endogenous hyperinsulinism.
• The patient also exhibited a high titer of immunoglobulin G insulin antibodies.

Findings:

• A biopsy-proven neuroendocrine tumor (insulinoma) was identified via endoscopic ultrasound.
• Successful treatment involved prednisone and radiofrequency ablation for the insulinoma.
• The patient achieved remission with steroid taper and no recurrence of symptoms.

Implications:

• This case underscores the importance of considering insulinoma in patients with unexplained hypoglycemia, even in the presence of insulin antibodies.
• The coexistence of insulinoma and insulin antibodies presents a unique diagnostic and therapeutic challenge.
• This report expands the understanding of rare endocrine disorders and their complex presentations.