Mature cystic teratoma of the pancreas: Role of endoscopic ultrasound

Cystic teratomas are a rare type of germ cell neoplasms derived from one or more germ layers. They can be classified as mature and immature teratomas based on the maturity of neuroectodermal elements within the tumor. Mature teratomas are benign, well-differentiated lesions, which may be solid or cystic. Mature cystic teratomas (MCTs) are also called dermoid cysts - a term likely coming from early surgical literature when the resected cysts resembled skin. Immature teratomas are malignant, undifferentiated tumors and generally solid. The most common location for MCTs is sacrococcygeus followed by ovaries and testes. MCTs in the pancreas are extremely rare with only few published case reports. Diagnosis of teratomas is challenging since there are no definitive preoperative diagnostic tests or pathognomonic findings. Even though EUS is commonly used for diagnosis of pancreatic cysts, the imaging features and cyst fluid characteristics of MCTs on EUS FNA have not been described. We describe a challenging case of a 65-year-old patient who had a 9 cm × 7 cm MCT in the body of the pancreas and discuss the role of EUS in diagnosis and management of these rare lesions. Complete surgical removal seems to be the current standard of care.