Periampullary pancreatic somatostatinoma

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.

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.

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

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.