Skip to content

Ovarian cysts and tumors: Pathology review




Reproductive system

Male and female reproductive system disorders
Male reproductive system disorders
Female reproductive system disorders
Reproductive system pathology review

Ovarian cysts and tumors: Pathology review


1 / 17 complete

USMLE® Step 1 style questions USMLE

17 questions

A 61-year-old woman, gravida 2 para 2, comes to the clinic due to pelvic discomfort and fatigue over the past 6 months. The patient was previously healthy, other than a history of polycystic ovarian syndrome. Menarche occurred at age 12, and menopause occurred 2 years ago. Both of the patient’s children were delivered via Cesarean sections due to personal preference. Family history is significant for breast cancer in her cousin at age 56 and colon cancer in her father at age 55. Vitals are within normal limits. BMI is 35 kg/m2. On physical examination, the abdomen is bloated, and shifting dullness is present. Pelvic examination reveals a left-sided adnexal mass. The patient undergoes a hysterectomy and bilateral salpingo-oophorectomy, followed by adjuvant chemotherapy. A pathohistological analysis is consistent with serous cystadenocarcinoma of the ovary. Which of the following is the most significant risk factor for this patient’s condition?


Content Reviewers:

Yifan Xiao, MD

65-year-old Rebecca presents to the clinic with several months of abdominal discomfort, bloating, and a change in bowel habits. Her past medical history is significant for endometriosis. Menarche was at age 10 and menopause at age 57. She has never been pregnant. On physical examination, a slightly painful nodule is palpated around the umbilicus. Transvaginal ultrasound showed a large, irregular cyst with heterogeneous fluid in her right ovary. Later that day, 6-year-old Gloriana is brought to the office by her mother, who is worried that her daughter is more “womanly” and taller than the other girls her age. Over the last few months, she has also occasionally complained of vague abdominal pain. Physical examination reveals coarse pubic hair and significant breast enlargement. The child’s height is also in the 96th percentile. Laboratory studies also showed increased inhibin b levels.

Based on the initial presentation, Rebecca and Gloriana’s symptoms are caused by some form of ovarian mass. Broadly speaking, ovarian masses include ovarian cysts and tumors. Starting with ovarian cysts, these are fluid-filled sacs on or in the ovaries and can be classified into simple and complex cysts.

Simple cysts are generally small, they contain a clear serous liquid, and have a smooth internal lining. The classic example is a follicular cyst which is a dominant follicle that fails to rupture before ovulation and keeps growing. This can happen, if say, the normal surge of LH that causes ovulation just doesn’t happen during a given menstrual cycle. In fact, follicular cysts are the most common type of ovarian mass in young individuals.

For your test, remember that if you encounter multiple follicular cysts, they are usually associated with polycystic ovary syndrome, or PCOS. This is caused by a dysfunction in the hypothalamic-pituitary-ovarian axis that causes chronic anovulation, which may lead to amenorrhea, or absent menstruation, and excess androgen production, which may lead to hirsutism.

Another type of simple cysts are the corpus luteum cysts. Normally, after ovulation, the follicle remnants become the corpus luteum, which regresses during the luteal phase. If instead of regressing, the corpus luteum continues to grow, then the arteries nourishing it can rupture and hemorrhage into the cyst. So a high-yield fact to know is that corpus luteum cysts are also called hemorrhagic cysts. The last kind of simple cysts are theca lutein cysts. These are caused by overstimulation by human chorionic gonadotropin, or hCG, a hormone that’s produced by the placenta, so they’re only seen in pregnancy. For your test, keep in mind that since hCG stimulates growth of the follicular theca cells and resting follicles can be found on both ovaries, these cysts are usually bilateral. Another important thing is that theca lutein cysts are much more likely to develop when there’s more hCG than usual, so the scenario will usually include multiple fetuses, or gestational trophoblastic disease, like hydatidiform mole, or choriocarcinoma.

Ok, now, the second category of cysts are complex cysts. These are generally large, have irregular borders, internal septations creating a multilocular appearance and the fluid inside these cysts tends to be heterogeneous, meaning there’s something other than fluid inside it. In many cases, a complex cyst could be part of an ovarian tumor.

Speaking of ovarian tumors, they can be divided into three categories: epithelial ovarian tumors, which derive from the surface epithelium of the ovary, germ cell tumors, which derive from primordial germ cells which are the cells that can give rise to all other tissues and organs, and sex cord-stromal tumors, which derive from sex cord-stromal cells that originate from the connective tissue of the ovary. For your exams, remember that epithelial tumors account for over seventy percent of all ovarian tumors. The other thirty percent comes from germ cell and sex cord-stromal tumors.

Epithelial ovarian tumors can then be subdivided into four types: serous, mucinous, endometrioid and transitional. Serous tumors are usually cystic and full of watery fluid. Mucinous-type tumors are similar to the serous type, but they’re full of a mucus-like fluid, which is where they get their name. Both serous and mucinous tumors can be benign, malignant, or borderline, meaning that they have a mix of benign and malignant characteristics.

The benign type is called serous or mucinous cystadenoma. Cystadenomas are usually a single cyst lined with simple cuboidal and columnar cells. On your test, they most commonly arise in premenopausal women who are between thirty and forty years old. What sets them apart is that serous cystadenomas, which are the most common type of ovarian cyst, tend to be bilateral and are lined with fallopian tube-like epithelium. On the other hand, only five to ten percent of mucinous cystadenomas are bilateral, and they are lined with mucous secreting epithelium.

The malignant type is called serous or mucinous cystadenocarcinoma. Cystadenocarcinomas have a thick, shaggy lining due to inflammation,