Ovarian cancer is a gynecologic cancer that arises from the ovaries. There are various types of ovarian cancer, depending on where in the ovaries the cancer started, and how the cells look under the microscope. The American Cancer Society lists three kinds of tissue in the ovary: epithelial, which is the outer tissue that covers the ovary; germ cells, which are found in the ovary and produce eggs; and stromal cells, which produce the hormones estrogen and progesterone. Differentiating between the tissues helps to determine what kind of ovarian cancer is present.
Epithelial Ovarian Tumors
Epithelial ovarian tumors are the most common ovarian tumors diagnosed, according to the pathology department at Johns Hopkins. These tumors form on the surface of the ovary and are differentiated based on how the tissue looks microscopically. These categories include serous, which looks like fallopian tube tissue; mucinous, which resembles GI tract or endocervical tissue; endometrioid, similar to the endometrium; clear cell, which also looks like endometrium; and transitional, or Brenner cells, which resembles urinary tract tissue. These kinds of tumors can be benign, or non-cancerous; borderline malignant; and malignant.
Germ Cell Tumors
These kinds of ovarian tumors arise from cells that produce the eggs in the ovary. Typically, these cancers are diagnosed in children and teenagers, but they can be diagnosed in women of any age. These tumors make up about 20 percent of ovarian cancer diagnoses. Germ cell tumors come in various forms, including dysgerminoma, yolk sac tumor, teratoma, embryonal carcinoma and choriocarcinoma.
Sex Cord-Stromal Tumors
Sex cord-stromal tumors make up about 10 percent of ovarian cancers and consist of varying cell types from sex cords and gonadal stroma. The American Cancer Society defines stromal cells as the cells in the ovary that produce hormones such as estrogen and progesterone. The most common cancers in this group are Granulosa cell tumors and Sertoli-Leydig cell tumors. Granulosa tumors are commonly found in postmenopausal women, and Sertoli-Leydig cancers are often found in women younger than 50 years old. The majority of these tumors are diagnosed in the early stages, compared with other kinds of ovarian cancers, which are typically found in late stages.
Primary Peritoneal Carcinoma
Primary peritoneal carcinoma, or PPC, is a rare cancer that closely resembles epithelial ovarian cancer and looks identical to it under the microscope. PPC starts in the lining of the abdominal cavity, which is called the peritoneum, and spreads along the walls of the abdomen and pelvis. Due to the similarities of the cells, PPC is typically treated by gynecologic oncologists and follows the same treatment as advanced ovarian cancer.
