Korean J Intern Med.  2003 Mar;18(1):45-49.

A Large Malignant Insulinoma: Case Report with Endosonographic, Immunohistochemical and Ultrastructural Features

• Lee CH
• Lee G
• Kim DH
• Kim NI
• Kim SJ
• Lee CW
• Song KH

Abstract

Malignant insulinoma in the beta cells of the pancreatic islet is rare and usually presented as hypoglycemia. We report a case of large malignant insulinoma in a 53-year-old Korean woman. A presumptive clinical diagnosis was made before surgery, based on the high plasma insulin-to-glucose ratio and a large solitary heterogeneous pancreatic mass by abdominal computed tomography and endosonography. The tumor measured 5.8X4.7X4.5 cm in dimension and showed capsular invasions and metastases in two of four peripancreatic lymph nodes. The tumor cells were strongly immunoreactive to insulin and had a high Ki-67 labeling index (13%) and atypical membranous electron-dense granules, ranging from 120 to 400 nm in diameter, in the cytoplasm on electron microscopy. The patient was treated by distal pancreatectomy with splenectomy and rapidly recovered without neurohypoglycemic symptoms. This case showed not only lymph node metastases, the most reliable parameter for malignancy in pancreatic endocrine tumors, but also other valid diagnostic clues, such as high Ki-67 labeling index, heterogeneous enodosonographic findings, capsular invasions with large tumor and pure atypical secretory granules.

Keyword

Hypoglycemia; Carcinoma; Islet Cell; Endosonography; Microscopy; Electron; Ki-67 Antigen

MeSH Terms

Biopsy, Needle
Endosonography
Female
Follow-Up Studies
Humans
Immunohistochemistry
Insulinoma/*diagnosis/*surgery
Islets of Langerhans/pathology/ultrastructure
Korea
Middle Aged
Neoplasm Staging
Pancreatectomy/*methods
Pancreatic Function Tests
Pancreatic Neoplasms/*diagnosis/*surgery
Risk Assessment
Treatment Outcome