Question: What is (are) Ovarian sex cord tumor with annular tubules ?
Answer: An ovarian sex cord tumor with annular tubules (SCTAT) is a tumor that grows from cells in the ovaries known as sex cord cells. As these cells grow, they form tube-like shapes in the tumor. SCTATs can develop in one or both ovaries, and may cause symptoms such as puberty at an exceptionally young age (precocious puberty), irregular menstrual cycles, or post-menopausal bleeding. Most ovarian SCTATs are benign. However, because there is a chance that an SCTAT may be malignant, treatment may include surgery to remove the tumor.
Source: GARD

Question: What causes Ovarian sex cord tumor with annular tubules ?
Answer: What causes an ovarian sex cord tumor with annular tubules? Approximately one third of ovarian sex cord tumors with annual tubules (SCTATs) develop because of an underlying genetic condition called Peutz Jeghers syndrome (PJS), which is caused by a mutation in the STK11 gene. In these genetic cases, many small SCTATs develop in both ovaries and are almost always benign. The remaining two thirds of ovarian SCTATs are not related to a genetic condition and develop as a single tumor in one ovary; up to 25% of SCTATs in this group may be malignant. Ovarian SCTATs not related to PJS have no known cause and are believed to occur by chance.
Source: GARD