The outcome of resected cystic pancreatic endocrine neoplasms: a case-matched analysis

Cystic pancreatic endocrine neoplasms (CPENs) are uncommon tumors with uncertain disease biology and ill-defined diagnostic features.

A prospectively maintained pancreatic cyst registry was queried, and 31 cases of CPEN that were resected between 1995 and 2010 were identified. Patient and lesion characteristics were detailed and compared with resected non-PEN cystic lesions. Recurrence and survival outcome were compared with 31 noncystic PENs matched for functional status, differentiation, size, World Health Organization classification, grade, and presence of metastases.

During the study period, CPENs accounted for 7% of resected pancreatic cysts (31/469) and 12% of resected PENs (31/255). CPENs were primarily sporadic (94%), solitary (87%), nonfunctioning (100%), and incidentally discovered (68%). The median diameter was 2.1 cm (range, 0.9-6.2 cm), and preoperative imaging identified septations in 29%, a solid component in 26%, and cyst wall enhancement or a characteristic hypervascular rim in 45% of cases. Preoperative imaging and/or cytology suggested the diagnosis of CPEN in 61%. Compared with resected nonendocrine cystic lesions, CPEN were less frequently symptomatic, less likely to contain septations, and smaller. Compared with matched noncystic PENs, CPENs had comparable demographic, radiologic, and pathologic features and statistically similar long-term outcome (5-year disease-free survival: CPEN: 100% vs PEN: 86%, P = .947).

In this study, CPENs were primarily asymptomatic small lesions that could be characterized in the majority of cases by cyst wall enhancement on preoperative imaging and/or cytologic assessment. No significant difference in recurrence or survival outcome was identified between cystic and noncystic PENs.