BACKGROUND. Pancreatic lymphangiomas are rare benign tumors, of which only a few cases have been reported in the literature. In this study, the authors present a series of primary pancreatic lymphangiomas. METHODS. Cases of nonepithelial pancreatic cystic tumors (lymphangiomas) diagnosed between 1966 and 1994 were retrieved from the Endocrine Pathology Registry of the Armed Forces Institute of Pathology. Histologic features (in 10 cases) as well as histochemical and immunohistochemical studies (in 6 cases) were reviewed. Long term patient follow-up data were obtained in 9 cases. RESULTS. The patients included 8 females and 2 males ages 2-61 years (mean age, 28.9 years) at initial presentation. The tumors were circumscribed and occurred predominantly (in 6 of 10 cases) in the tail of the pancreas. The multicystic, serous, or chylous fluid-filled cystic tumors ranged from 3 to 20 cm (average, 12.7 cm) in greatest dimension. Histologically, the tumors consisted of multilocular cystic spaces of various sizes, lined by endothelial cells. The stroma contained smooth muscle and mature lymphocytes. Immunohistochemistry determined the endothelial lining cells to be factor VIII-R antigen and CD31 positive (in all cases tested) but usually CD34 negative. All patients for whom follow-up data were obtained (n = 9) were alive without evidence of disease an average of 7.2 years after initial diagnosis. CONCLUSIONS. Pancreatic lymphangiomas occur predominantly in females within a wide age range. Multilocular, fluid-filled cysts, with endothelial immunoreactivity for factor VIII-R antigen and CD31, are characteristic of these tumors. Complete surgical excision of these benign tumors resulted in excellent long term prognoses for all patients studied
