Minute non-functioning islet cell tumor accompanied by large lymph node metastasis in a 61-year-old male is reported. The patient was reffered to us because of upper abdominal pain and high CEA level in blood. Physical examination revealed abdominal tumor but close evaluation including abdominal CT and angiography failed to establish the definite diagnosis. Operation showed a fist-sized lymph node swelling beneath the pancreas suggesting metastasis. But it was impossible to identify the primary focus and only lymph node biopsy was performed. He died on 31-post-operative-day. Autopsy revealed the minute non-functining islet cell carcinoma with a 2mm diameter as the primary origin.
In general, the non-functioning islet cell tumor exerts relatively low malignancy, and even in a malignant case, the primary focus grows expansively and forms a large tumor. This case seems to be a rare one developing mainly to the lymph node.