Lymphangioma of the pancreas with "ovarian-like" mesenchymal stroma: a case report with emphasis on histogenesis.

Pancreatic lymphangiomas, which occur predominantly in women, are rare and account for only 1% of all lymphangiomas. The characteristic histologic features include multiple cysts lined by endothelial cells, irregularly distributed smooth muscle cells, and lymphoid aggregates in the wall of the cyst. We describe a 36-year-old woman with lymphangioma of the pancreas with "ovarian-like" mesenchymal stroma in the wall. This stroma, composed of uncommitted mesenchymal cells, has not been described previously in the wall of pancreatic lymphangiomas. Multiple small lymphatic channels that are found in this stroma recapitulate the development of lymphatic channels in the embryo. Lymphangioma of the pancreas may arise from distension of these lymphatic channels. Pancreatic lymphangioma may, therefore, be a developmental anomaly rather than a true neoplasm.