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Case Reports in Medicine
Volume 2011, Article ID 930904, 5 pages
Case Report

Hypoglycemic Syndrome in a Patient with Proinsulin-Only Secreting Pancreatic Adenoma (Proinsulinoma)

1Department of Clinical and Experimental Medicine, Metabolic Division, Medical School, University of Padova, 35100 Padova, Italy
2Department of Medical and Surgical Sciences, Medical School, University of Padova, 35100 Padova, Italy
3Department of Medical Diagnostic Sciences and Special Therapies, Medical School, University of Padova, 35100 Padova, Italy

Received 13 February 2011; Accepted 15 May 2011

Academic Editor: Dara P. Schuster

Copyright © 2011 Gian Paolo Fadini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We describe an unusual case of hypoglycemic syndrome in a 69-year old woman with a proinsulin-only secreting pancreatic endocrine adenoma. The clinical history was highly suggestive of an organic hypoglycemia, with normal or relatively low insulin concentrations and elevated proinsulin levels. Magnetic resonance and computed tomography of the abdomen showed a 1 cm pancreatic nodule and multiple accessory spleens. The diagnosis was confirmed by selective angiography, showing location and vascularization of the nodule, despite no response to intra-arterial calcium. After resection, the hypoglycemic syndrome resolved. The surgical specimen was comprised of a neuroendocrine adenomatous tissue with high proinsulin immunoreactivity. Study of this unusual case of proinsulinoma underlines (i) the need to assay proinsulin in patients with hypoglycemia and normal immunoreactive insulin, (ii) the differential diagnosis in the presence of accessory spleens, (iii) the unresponsiveness to intra-arterial calcium stimulation, and (iv) the extensive evaluation needed to reach a final diagnosis.