Giant malignant insulinoma

Abstract

Insulinomas are the most common pancreatic neuroendocrine tumors. Most insulinomas are benign, small, intrapancreatic solid tumors and only large tumors have a tendency for malignancy. Most patients present with symptoms of hypoglycemia that are relieved with the administration of glucose. We herein present the case of a 75-year-old woman who presented with an acute hypoglycemic episode. Subsequent laboratory and radiological studies established the diagnosis of a 17-cm malignant insulinoma, with local invasion to the left kidney, lymph node metastasis, and hepatic metastases. Patient symptoms, diagnostic and imaging work-up and surgical management of both the primary and the metastatic disease are reviewed.

Keywords: Giant tumor; Insulinoma; PNET.

Fig. 1. (A) Coronal volume rendering reformatted image demonstrates patent splenic artery surrounded by tumor (arrows). (B) Coronal maximum intensity projection reformatted image depicting patent portal and splenic vein (arrows).

Fig. 2. Post contrast axial CT image during arterial phase. Multiple hypervascular metastases are seen in liver.

Fig. 3. Post contrast reformatted CT images (A: coronal MPR, B: oblique MPR) during arterial phase. There is heterogeneously enhancing lobulated mass (arrows in A) in pancreatic tail with central necrosis (black block arrow in A). Coarse calcifications are also present within necrotic areas (white arrowhead in A). Large enhancing masses are also evident at level of left renal hilum (arrows in B) and at left retrocrural space (white arrow in A). Multiple hypervascular metastases are seen in liver (block arrowheads in B). MPR, multiplanar reformatting.

Fig. 4. (A, B) Microphotograph showing section from tumor with acinar pattern (H&E: A, ×100; B, ×400).

Fig. 5. (A, B) Immunohistochemical expression of cytokeratin E1 from tumor cells. Streptavidin-biotin peroxidase (A, ×100; B, ×400). (C, D) Immunohistochemical expression of cytokeratin E3 from tumor cells. Streptavidin-biotin peroxidase (A, ×100; B, ×400).

Fig. 6. (A, B) Immunohistochemical expression of polyclonal CEA from tumor cells. Streptavidin-biotin peroxidase (A, ×100; B, ×400). (C, D) Immunohistochemical expression of insulin from tumor cells. Streptavidin-biotin peroxidase (A, ×100; B, ×400).