The growing mass may cause pain if ovarian torsion develops. Symptoms can be caused by a mass pressing on the other abdominopelvic organs or from metastases. If these symptoms start to occur more often or more severely than usual, especially after no significant history of such symptoms, ovarian cancer is considered. Metastases may cause a Sister Mary Joseph nodule. Rarely, teratomas can cause growing teratoma syndrome or peritoneal gliomatosis. Some experience menometrorrhagia and abnormal vaginal bleeding after menopause in most cases. Other common symptoms include hirsutism, abdominal pain, virilization, and an adnexal mass.

In adolescents or children with ovarian tumors, symptoms can include severe abdominal pain, irritation of the peritoneum, or bleeding. Symptoms of sex cord-stromal tumors produce hormones that can affect the development of secondary sex characteristics. Sex cord-stromal tumors in prepubertal children may be manifested by early puberty; abdominal pain and distension are also common. Adolescents with sex cord-stromal tumors may experience amenorrhea. As the cancer becomes more advanced, it can cause an accumulation of fluid in the abdomen. If the malignancy has not been diagnosed by the time it causes ascites, it is typically diagnosed shortly thereafter. Advanced cancers can also cause abdominal masses, lymph node masses, or pleural effusion.

Choriocarcinoma is a malignant, trophoblastic cancer, usually of the placenta. It is characterized by "early hematogenous spread" to the lungs. It belongs to the malignant end of the spectrum in gestational trophoblastic disease (GTD). It is also classified as a germ cell tumor and may arise in the testis or ovary.

Gestational trophoblastic disease (GTD) is a term used for a group of pregnancy-related tumours. These tumours are rare, and they appear when cells in the womb start to proliferate uncontrollably. The cells that form gestational trophoblastic tumours are called trophoblasts and come from tissue that grows to form the placenta during pregnancy.

There are several different types of GTD. Hydatidiform moles are benign in most cases, but sometimes may develop into invasive moles, or, in rare cases, into choriocarcinoma, which is likely to spread quickly, but which is very sensitive to chemotherapy, and has a very good prognosis. Gestational trophoblasts are of particular interest to cell biologists because, like cancer, these cells invade tissue (the uterus), but unlike cancer, they sometimes "know" when to stop.

GTD can simulate pregnancy, because the uterus may contain fetal tissue, albeit abnormal. This tissue may grow at the same rate as a normal pregnancy, and produces chorionic gonadotropin, a hormone which is measured to monitor fetal well-being.

While GTD overwhelmingly affects women of child-bearing age, it may rarely occur in postmenopausal women.

Gestational trophoblastic disease (GTD) may also be called gestational trophoblastic tumour (GTT).

Hydatidiform mole (one type of GTD) may also be called molar pregnancy.

Persistent disease; persistent GTD: If there is any evidence of persistence of GTD, usually defined as persistent elevation of beta hCG (see «Diagnosis» below), the condition may also be referred to as gestational trophoblastic neoplasia (GTN).

Ovarian pregnancy refers to an ectopic pregnancy that is located in the ovary. Typically the egg cell is not released or picked up at ovulation, but fertilized within the ovary where the pregnancy implants. Such a pregnancy usually does not proceed past the first four weeks of pregnancy. An untreated ovarian pregnancy causes potentially fatal intraabdominal bleeding and thus may become a medical emergency.

Some or all of the following symptoms may be present, though it is possible not to experience any symptoms:

- Abdominal pain. Dull aching pain within the abdomen or pelvis, especially during intercourse.

- Uterine bleeding. Pain during or shortly after beginning or end of menstrual period; irregular periods, or abnormal uterine bleeding or spotting.

- Fullness, heaviness, pressure, swelling, or bloating in the abdomen.

- When a cyst ruptures from the ovary, there may be sudden and sharp pain in the lower abdomen on one side.

- Change in frequency or ease of urination (such as inability to fully empty the bladder), or difficulty with bowel movements due to pressure on adjacent pelvic anatomy.

- Constitutional symptoms such as fatigue, headaches

- Nausea or vomiting

- Weight gain

Other symptoms may depend on the cause of the cysts:

- Symptoms that may occur if the cause of the cysts is polycystic ovarian syndrome (PCOS) may include increased facial hair or body hair, acne, obesity and infertility.

- If the cause is endometriosis, then periods may be heavy, and intercourse painful.

The effect of cysts not related to PCOS on fertility is unclear.

Trophoblastic neoplasms derive from trophoblastic tissue. Examples include:

- Choriocarcinoma

- Hydatidiform mole

Choriocarcinoma of the placenta during pregnancy is preceded by:

- hydatidiform mole (50% of cases)

- spontaneous abortion (20% of cases)

- ectopic pregnancy (2% of cases)

- normal term pregnancy (20–30% of cases)

- hyperemesis gravidarum

Rarely, choriocarcinoma occurs in primary locations other than the placenta; very rarely, it occurs in testicles. Although trophoblastic components are common components of mixed germ cell tumors, pure choriocarcinoma of the adult testis is rare. Pure choriocarcinoma of the testis represents the most aggressive pathologic variant of germ cell tumors in adults, characteristically with early hematogenous and lymphatic metastatic spread. Because of early spread and inherent resistance to anticancer drugs, patients have poor prognosis. Elements of choriocarcinoma in a mixed testicular tumor have no prognostic importance.

Choriocarcinomas can also occur in the ovaries.

Trophoblastic neoplasms are neoplasms which derive from trophoblastic tissue.

Examples include:

- choriocarcinoma

- hydatidiform mole

If ovarian hormones are present after the ovaries are removed can be a sign that ovarian tissue still remains. Signs and symptoms may include pelvic pain, a pelvic mass, or the absence of menopause after oophorectomy. Factors may include pelvic adhesions (limiting ability to see the ovary or causing it to adhere to other tissues); anatomic variations; bleeding during surgery; or poor surgical technique. Treatment is indicated for people with symptoms and typically involves surgery to remove the residual tissue. Therapy for those who refuse surgery, cannot have surgery, or do not have a pelvic mass may include hormonal therapy to suppress ovarian function.

Some women have symptoms consistent with endometriosis, including difficult or painful intercourse; urinary symptoms; or bowel symptoms. It is likely that some women with ORS don't have any symptoms, but the rate of this is unknown.In most cases, symptoms occur within the first five years of the oophorectomy, although there are reports of ORS presenting 20 years after the initial surgery.

Ovarian diseases can be classified as endocrine disorders or as a disorders of the reproductive system.

If the egg fails to release from the follicle in the ovary an ovarian cyst may form. Small ovarian cysts are common in healthy women. Some women have more follicles than usual (polycystic ovary syndrome), which inhibits the follicles to grow normally and this will cause cycle irregularities.

Other conditions include:

- Ovarian cancer

- Luteoma

- Hypogonadism

- Hyperthecosis

A ruptured ovarian cyst is usually self-limiting, and only requires keeping an eye on the situation and pain medications. The main symptom is abdominal pain, which may last a few days to a several weeks, but they can also be asymptomatic. Rupture of large ovarian cysts can cause bleeding inside the abdominal cavity and in some cases shock.

Benign tumors of the ovary include ovarian cysts, such as borderline tumor cysts.

OHSS is divided into the categories mild, moderate, severe, and critical.

In mild forms of OHSS the ovaries are enlarged (5–12 cm) and there may be additional accumulation of ascites with mild abdominal distension, abdominal pain, nausea, and diarrhea. In severe forms of OHSS there may be hemoconcentration, thrombosis, distension, oliguria (decreased urine production), pleural effusion, and respiratory distress. Early OHSS develops before pregnancy testing and late OHSS is seen in early pregnancy.

Criteria for severe OHSS include enlarged ovary, ascites, hematocrit > 45%, WBC > 15,000, oliguria, creatinine 1.0-1.5 mg/dl, creatinine clearance > 50 ml/min, liver dysfunction, and anasarca. Critical OHSS includes enlarged ovary, tense ascites with hydrothorax and pericardial effusion, hematocrit > 55%, WBC > 25,000, oligoanuria, creatinine > 1.6 mg/dl, creatinine clearance < 50 ml/min, renal failure, thromboembolic phenomena, and ARDS.

Patients with ovarian torsion often present with sudden onset of sharp and usually unilateral lower abdominal pain, in 70% of cases accompanied by nausea and vomiting.

Ovarian torsion (OT) is the rotation of the ovary at its to such a degree as to occlude the ovarian artery and/or vein.

Symptoms are set into 3 categories: mild, moderate, and severe. Mild symptoms include abdominal bloating and feeling of fullness, nausea, diarrhea, and slight weight gain. Moderate symptoms include excessive weight gain (weight gain of greater than 2 pounds per day), increased abdominal girth, vomiting, diarrhea, darker urine, decreased urine output, excessive thirst, and skin and/or hair feeling dry (in addition to mild symptoms). Severe symptoms are fullness/bloating above the waist, shortness of breath, pleural effusion, urination significantly darker or has ceased, calf and chest pains, marked abdominal bloating or distention, and lower abdominal pains (in addition to mild and moderate symptoms).

It can, however, grow to almost 10 cm (4 inches) in diameter and has the potential to bleed into itself or twist the ovary, causing pelvic or abdominal pain. If it fills with blood, the cyst may rupture, causing internal bleeding and sharp pain. This pain disappears within a few days of the rupture. Rarely, it may cause the ovary to twist around the ovarian ligament and can cut off the blood flow to the ovary. This is known as ovarian torsion and causes pain and other symptoms.

Residual ovary syndrome or ovarian remnant syndrome is a condition that occurs when ovarian tissue is left behind following oophorectomy, causing development of a pelvic mass, pelvic pain, and occasionally dyspareunia. Ovarian remnant syndrome (ORS) is characterized by the presence of residual ovarian tissue after a woman has had surgery to remove one ovary or both ovaries (oophorectomy).

Molar pregnancies usually present with painless vaginal bleeding in the fourth to fifth month of pregnancy. The uterus may be larger than expected, or the ovaries may be enlarged. There may also be more vomiting than would be expected (hyperemesis). Sometimes there is an increase in blood pressure along with protein in the urine. Blood tests will show very high levels of human chorionic gonadotropin (hCG).

Ovarian cancer is classified according to the histology of the tumor, obtained in a pathology report. Histology dictates many aspects of clinical treatment, management, and prognosis.

- Surface epithelial-stromal tumours, also known as ovarian epithelial tumors, are the most common type of ovarian cancer. It includes serous tumour, endometrioid tumor, and mucinous tumour. They can be benign (cystadenoma) or malignant (cystadenocarcinoma). Less common tumors are malignant Brenner tumor and transitional cell carcinoma of the ovary.

- Sex cord-stromal tumor, including estrogen-producing granulosa cell tumor and virilizing Sertoli-Leydig cell tumor or arrhenoblastoma, accounts for 8% of ovarian cancers.

- Germ cell tumor accounts for approximately 30% of ovarian tumors but only 5% of ovarian cancers, because most germ cell tumors are teratomas and most teratomas are benign. Germ cell tumors tend to occur in young women (20's-30's) and girls. Whilst overall the prognosis of germ cell tumors tend to be favourable, it can vary substantially with specific histology: for instance, the prognosis of the most common germ cell tumor (dysgerminomas) tends to be good, whilst the second most common (endodermal sinus tumor) tends to have a poor prognosis. In addition, the cancer markers used vary with tumor type: choriocarcinomas are monitored with beta-HCG; dysgerminomas with LDH; and endodermal sinus tumors with alpha-fetoprotein.

- Mixed tumors, containing elements of more than one of the above classes of tumor histology.

Placental site trophoblastic tumor is a form of gestational trophoblastic disease, which is thought to arise from intermediate trophoblast.

It may secrete human placental lactogen (human chorionic somatomammotropin), and result in a false-positive pregnancy test.

Placental site trophoblastic tumor is a monophasic neoplasm of the implantation site intermediate trophoblast, and usually a benign lesion, which comprises less than 2% of all gestational trophoblastic proliferations. Preceding conditions include molar pregnancy (5%). Compared to choriocarcinoma or invasive mole, hemorrhage is less conspicuous and serum β-HCG level is low, making early diagnosis difficult.

Immunohistochemistry: Often stains with hPL, keratin, Mel-CAM, EGFR.

Prognosis: 10–20% of cases metastase leading to death.

Treatment: Because chemotherapy is ineffective; the patient should undergo hysterectomy.

Krukenberg tumors often come to the attention when they cause abdominal or pelvic pain, bloating, ascites, or pain during sexual intercourse. Krukenberg tumors can occasionally provoke a reaction of the ovarian stroma which leads to hormone production, that results in vaginal bleeding, a change in menstrual habits, or hirsutism, or occasionally virilization as a main symptom.

All these symptoms are non-specific and can also arise with a range of problems other than cancer, and a diagnosis can only be made following confirmatory investigations such as computed tomography (CT) scans, laparotomy and/or a biopsy of the ovary.

Papillary serous cystadenocarcinomas may exhibit psammoma bodies upon histopathology.