This is a tumor of ovarian surface epithelium. These are the most common ovarian neoplasms. Such neoplasms may be lined by epithelium that is serous or mucinous. Pictured here is a serous cystadenoma. This benign serous tumor was filled with pale yellow serous fluid in only a single (unilocular) cavity. Mucinous tumors are filled with sticky mucin and tend to be multiloculated. Benign epithelial ovarian tumors may be bilateral.

---