Ovarian Sex Cord Tumor with Annular Tubules (EFO_1000430) is an ovarian sex cord-stromal tumor characterized by the presence of Sertoli cells forming annular tubules. It may be associated with Peutz-Jeghers syndrome. Cases associated with Peutz-Jeghers syndrome have followed a benign clinical course. Cases which are not associated with Peutz-Jeghers syndrome have been reported having a clinically malignant course.