Malignant Insulinoma: Report of Unusual Site of Recurrence
Silvestri S1, Campra D1, De Angelis C2, Chiusa L3, Cassine D1, Cucinelli M1, Maglione V1, Fronda GR1
1Seventh Division of General Surgery, 2Department of Gastroenterology, 3Second Department of Pathology, 'ASO S.Giovanni Battista - Molinette'. Turin, Italy
ABSTRACT
Context Malignant insulinoma (MI) is a rare neuroendocrine neoplasia. It accounts for 5-10% of all pancreatic insulinomas. There are no specific morphological, biochemical or genetic features that clearly identify MI. Malignancy can be defined only by histological and immunohistochemical examination. Case report In 2002 a 28-year-old woman underwent a laparoscopic enucleation for a preoperative documented insulinoma. The histopathological examination revealed a neuroendocrine tumor with angioinvasive features and high mitotic index with clear resection margins. During follow up, levels of glucose, insulin and C-peptide were in range of normality; no hypoglycemic episodes occurred. In November 2006 the patient had a hypoglycemic episode. TC scan revealed an hypodense sub glissonian and hypervascularized lesion in VI hepatic segment and another focal lesion in the pancreatic body; a contrast-enhanced EUS confirmed the TC evidence of fibro-necrotic nature of the pancreatic lesion. At laparotomy, it was found an unknown nodular subgerotian mass, which was resected. No hepatic lesions were found. The histological examination revealed the presence of MI with the same features of the previous one, examined in 2002. No complications were observed in postoperative period. Conclusion Laparoscopic approach is a feasible and safe procedure in neuroendocrine pancreatic tumor; in young patients and in case of single nodular lesion, laparoscopy could be the best choice. Recurrence of MI, mainly for hepatic localization, are well known even some years after the diagnosis of the primary tumor. However, a sub gerotian secondarism has never been described in the literature. This finding opens up this question: a real recurrence of the primary tumor or a new independent MI, deriving from aberrant pancreatic tissue? In this case the histological examination did not reveal pancreatic tissue, suggesting a recurrence of the primary MI in a unusual site. Patients who underwent a conservative local excision may need a surgical revision after the histological finding of malignancy in order to enlarge the resection margins. A more aggressive follow up for MI should be recommended.
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