Duodenal somatostatinoma of the ampulla of vater diagnosed by endoscopic fine needle aspiration biopsy: a case report

Two synchronous somatostatinomas of the duodenum and pancreatic head in one patient

Somatostatinomas are extremely rare neuroendocrine tumors of the gastrointestinal tract, first described in the pancreas in 1977 and in the duodenum in 1979. They may be functional and cause somatostatinoma or inhibitory syndrome, but more frequently are non-functioning pancreatic endocrine tumors that produce somatostatin alone. They are usually single, malignant, large lesions, frequently associated with metastases, and generally with poor prognosis. We present the unique case of a 57-year-old woman with two synchronous non-functioning somatostatinomas, one solid duodenal lesion and one cystic lesion within the head of the pancreas, that were successfully resected with a pylorus-preserving Whipple’s procedure. No secondaries were found in the liver, or in any of the removed regional lymph nodes. The patient had an uneventful recovery, and remains well and symptom-free at 18 mo postoperatively. This is an extremely rare case of a patient with two synchronous somatostatinomas of the duodenum and the pancreas. The condition is discussed with reference to the literature.

Periampullary pancreatic somatostatinoma

BACKGROUND

Somatostatinomas involving the gastrointestinal tract are extremely rare neoplasms that typically present with indolent, nonspecific symptoms in the absence of systemic neuroendocrine manifestations that characterize the somatostatinoma syndrome. Because of a relatively large size at the time of presentation (average diameter of 5 cm) and common location within the head of the pancreas, the Whipple procedure (pancreaticoduodenectomy) serves as the predominant modality for curative and palliative surgical approaches.

METHODS

Two cases of somatostatinoma involving the minor duodenal papilla with concomitant pancreatic divisum were reviewed, with a general overview of this unique islet cell tumor.

RESULTS

Unlike typical somatostatinomas, these two tumors were subcentimeter in size but were associated with synchronous regional metastasis.

CONCLUSIONS

Somatostatinomas are often associated with regional and/or portal metastases at the time of diagnosis, and only 60% to 70% of surgical cases result in complete tumor resection. Predictors of an unfavorable prognosis include size >3 cm, poor cytological differentiation, regional and/or portal metastasis, and incomplete surgical resection. Even in the presence of synchronous metastases, the 5-year overall survival for patients with somatostatinoma is approximately 40%. Currently, there are no clinical trials demonstrating significant improvement in survival with the use of adjuvant therapy.