Minute malignant islet cell tumor of the pancreas: report of a case

Area of Science:

• Gastroenterology and Hepatology
• Surgical Oncology
• Diagnostic Imaging

Background:

• Islet cell tumors (neuroendocrine tumors) can be challenging to diagnose due to their small size and varied presentation.
• Accurate localization and characterization are critical for appropriate surgical management.
• Advanced imaging modalities play a key role in the diagnostic workup of pancreatic lesions.

Observation:

• A 73-year-old Japanese man presented with gastric cancer, incidentally found to have a 7 mm hypoechoic pancreatic head mass on preoperative ultrasonography (US).
• Standard imaging techniques including endoscopic retrograde pancreatography, angiography, CT, and MRI were inconclusive for tumor characterization and localization.
• Endoscopic US and intraoperative US provided definitive visualization of the minute pancreatic mass.

Findings:

• Intraoperative fine-needle aspiration cytology confirmed an islet cell tumor but was insufficient for malignancy grading.
• Histologic examination of the enucleated tumor established the diagnosis and grade of malignancy.
• The combined use of multiple imaging modalities, particularly US, was essential for successful diagnosis and surgical planning.

Implications:

• This case highlights the diagnostic utility of endoscopic and intraoperative ultrasonography for small, elusive pancreatic islet cell tumors.
• Accurate preoperative diagnosis and grading are vital for determining the optimal surgical approach, potentially avoiding more extensive resections.
• The findings underscore the importance of a multimodal imaging strategy in managing pancreatic neuroendocrine tumors.