Lymphoepithelial cyst of the pancreas.

A rare cystic lesion of the pancreas is reported. Morphologically, this unilocular cyst was filled with keratin material and lined by mature, keratinizing squamous epithelium; it was surrounded by lymphoid tissue and also focally by pancreatic tissue. Clinically, the lesion was associated with diarrhea and abdominal pain, both of which promptly disappeared after its removal. Although the histogenesis of this lesion is not known, it can be histologically differentiated from other pancreatic and retroperitoneal cysts. We propose the name "lymphoepithelial cyst" for this lesion and note that only one similar case has been described previously.