Normalization of Prediabetic Hemoglobin A1c (HbA1c) Levels After the Surgical Removal of a Serotonin-Secreting Neuroendocrine Tumor

• Published in: Cureus 2024, Vol.16 (4), p.e57376-e57376
• Main Authors: Tskitishvili, Aleksandre, Lobjanidze, Mariam, Turmanishvili, Zurabi, Mamulashvili, Nikoloz, Bejanishvili, Tamar
• Format: Report
• Language: English
• ISSN: 2168-8184; 2168-8184
• DOI: 10.7759/cureus.57376

Neuroendocrine tumors (NETs) are rare. When present, they often produce serotonin and are called carcinoids. Serotonin-secreting NETs can present with or without carcinoid syndrome. Although the idea of serotonin-secreting NETs potentially altering glucose metabolism is not new, data around this issue has been scarce, with only a few limited studies and case reports. We present a case where a female patient's prediabetic hemoglobin A1C levels normalized after removing serotonin-secreting NET. Before removal, the patient had locally metastatic carcinoid and serotonin-related intractable diarrhea but did not exhibit any other sign of carcinoid syndrome, including flushing, which is considered a hallmark. Therefore, in suggestive clinical contexts, this case points to the possibility of impaired glucose tolerance being an early clinical sign of carcinoid that could aid in serotonin-secreting NET diagnosis before it manifests as overt carcinoid syndrome.