Endocrine Abstracts

Introduction: Gastrinoma is rare gastrin-secreting neuroendocrine tumor (NET), usually located in the pancreas or duodenum. The most common presentations of gastrin secreting tumor is Zollinger-Ellison Syndrome (ZES). Only about 10% of patients have non demonstrable ulcer.

Case presentation: A 67 years old female, with premature menopause, mild hypothyroidism with optimal replacement treatment, osteopenia and history of chronic gastritis, is admitted to our clinic accusing debilitating diarrhea (10 episodes/day), about 1 year before presentation. Clinical examination was normal, excepting abdominal tenderness. Carcinoid syndrome was suspected, and neuroendocrine tumor markers were measured, revealing high levels of gastrin (5 × upper limit of normal) and Chromogranin A (CGA). Neuron Specific Enolaze, Serotonin and urinary 5 hydroxyindoleacetic acid were normal. Prolactin, PTH and calcium levels were normal. Also Thyroid function was normal. Upper endoscopy performed before admission did not reveal any gastric or duodenal ulcers. Classic imaging testing (CT and MRI) revealed no images suggesting a neuroendocrine tumor, but showed an adrenal incidentaloma. Lab test revealed normal values of ACTH, Cortisol, Dehydroepiandrosterone Sulfate, plasma Metanephrines and Normetanephrines, Rennin and Aldosterone. SPECT-CT somatostatin receptor scintigraphy (SRS) with 99 mTc-Tektrotyd was performed, and revealed high accumulation in the head and uncinate process of the pancreas. She was referred for surgical evaluation, but the tumor was considered inoperable. Somatostatin analogues (SSA) treatment was started in association with proton pump inhibitors (PPI) and sucralfate. At the 3 months follow up the patient presented with improvement of symptoms (3–4 normal stools/day). Also lab test revealed normalisation of gastrin and CGA. SRS with 99 mTc-Tektrotyd was repeated and revealed significant shrinkage of the tumor. Due to SSA treatment patient developed secondary diabetes mellitus, and was started on metformin.

Conclusion: Although ZES is the most common presentation of gastrinoma, 10% of patients do not present typical symptoms. Despite the fact that surgical treatment is the only curative treatment, SSA analogues is a viable treatment option in selected cases, especially when surgery is not possible, and may lead to improvement of symptoms and also induce morphologic and functional response.