Primary strumal carcinoid tumor of the ovary: A pregnant patient exhibiting severe constipation and CEA elevation

► We present a rare case of a PYY-positive primary strumal carcinoid tumor of the ovary during pregnancy.
► MRI was useful for the preoperative diagnosis, and the prenatal course was uneventful after the operation.
► Colitis due to severe constipation caused by PYY, which is an inhibitor of intestinal mobility, might induce serum CEA elevation.