The tumor has a lobular distribution of annular tubules with characteristic morphology, which will not be described further. Regarding its cells, some scholars believe that they are Sertoli cells, while others believe that they are granulosa cells. Some cells morphologically resemble granulosa cells and have Call-Exner vesicles. Electron microscopically, these tumor cells have the ultrastructural characteristics of Sertoli cells. Some people may consider amphiblastoma, when in fact true amphiblastoma is very rare. The new WHO classification of ovarian tumors no longer includes amphiblastoma, and most of them are classified as mixed sex cord mesenchymal tumors, such as Sertoli-Lydig cell tumors. Regarding sex cord tumors with annular tubules, they are actually divided into two major groups: those with Peutz-Jeghers syndrome and those with dissemination. The former are all benign, while the latter are about 20% malignant and can metastasize. Those with Peutz-Jeghers syndrome are often bilateral, small in size, mostly less than 3 cm, multifocal, and more commonly calcified, while a few patients have microscopic adenocarcinoma of the cervix; whereas most of the disseminated cases are unilateral, large, visible masses, unifocal, less often calcified, and not accompanied by microscopic adenocarcinoma. In the disseminated cases, the benignity and malignancy are difficult to distinguish histomorphologically; therefore, the tumor is classified as 8623/1 in the ICD-O code, which means that it is of undetermined benign, malignant nature or low malignant potential.