A 41 year old surgeon presented with several months of epigastric pain. A CT scan was performed which revealed multiple masses in the liver, the largest of which measured approximately 7.4 cm in diameter. Some of these lesions demonstrated high peripheral density suggestive of calcification; no obvious pancreatic mass was noted. A CT guided biopsy of one of the liver lesions revealed metastatic neuroendocrine tumor, with evidence of psammoma bodies.
An EUS of the pancreas was performed to evaluate for a primary lesion, and revealed a heterogeneous isoechoic lesion in the head of the pancreas measuring approximately 2.5 cm in diameter. FNA was performed of the lesion using a 25G needle. Survey of the left lobe of the liver revealed multiple small lesions including a large hyperechoic calcified mass.
On site FNA diff quik stain showed scattered larger cells with plasmacytoid features, suggestive of a neuroendocrine lesion. It also revealed psammoma bodies. Additional immunohistochemical studies were positive for somatostatin.
These findings were consistent with metastatic somatostatinoma of pancreatic origin. The patient underwent a Whipple procedure for resection of the primary pancreatic lesion, and chemoembolization for hepatic metastases.
Generally, pancreatic neuroendocrine tumors (PNETs) account for less than 5% of all pancreatic neoplasms. Somatostatinomas being particularly rare, account for < 1% of all pancreatic neuroendocrine tumors.
On presentation somatostatinomas are usually large, located in the head of the pancreas and can be metastatic 70% of the time.
While surgical resection is the treatment of choice in early stages, it is rarely possible in metastatic disease. Some patients will require surgical debulking if they become symptomatic, however many patients are asymptomatic and follow a clinically indolent course. The 5 and 10-year survival rates for metastatic (stage IV) pancreatic neuroendocrine tumors such as somatostatinoma after surgical resection are 15.5 and 5.1%.
Prashant Kedia, MD, Mount Sinai Medical Center
Ron Lee, MD, Mount Sinai Medical Center
Kalpesh Patel, MD, Mount Sinai Medical Center
Michelle Kim, MD, Mount Sinai Medical Center