Insulinoma: A multicenter, retrospective analysis of three decades of experience (1983–2014)

Abstract

Abstract Objective To analyze the clinical features, diagnostic procedures, treatment, and clinical outcome of insulinomas diagnosed and treated in the period 1983–2014 in four Spanish hospitals. Methods All patients with either biochemical and morphological criteria of insulinoma and/or histological demonstration of insulin-secreting tumor were included. Results Twenty-nine patients [23 women (79.3%); mean age 48.7 ± 17.4 years (range, 16–74)] were recruited. Twenty-six patients (89.7%) had sporadic tumors, and the rest (3 women, 10.3%) developed in the context of multiple endocrine neoplasia type 1. There were 3 (10.3%) multiple insulinomas, one associated with multiple endocrine neoplasia type 1, and two (6.9%) malignant insulinomas, both sporadic. Most patients (n = 18, 62.1%) had fasting hypoglycemia, about a third (31%) both postprandial and fasting hypoglycemia, and 6.9% postprandial hypoglycemia only. Time to glucose nadir (37.3 ± 6.5 mg/dl) in the fasting test was 9.0 ± 4.4 h, with maximal insulin levels of 25.0 ± 20.3 μU/ml. Abdominal CT detected insulinoma in 75% of patients. Twenty-seven (93.1%) patients underwent surgery [enucleation, 18 (66.7%) and subtotal pancreatectomy, 9 (33.3%); tumor size, 1.7 ± 0.7 cm]. Surgery achieved cure in the majority (n = 24, 88.9%) of patients. Conclusion In our setting, insulinoma is usually a benign, small, and solitary tumor, mainly affecting women aged 45–50 years, and usually localized with abdominal CT. The most commonly used surgical technique is enucleation, which achieves a high cure rate.