Pathology > Gynecologic > Ovary > Nonneoplastic Lesions
Objectives Anat & Hist Nonneoplastic Lesions Neoplasms

II. Nonneoplastic Lesions

  1. Solitary Cysts
  • Follicular cysts

These represent exaggeration of the usually cystic graafian follicle.

Clinical features

Follicular cysts are common occurring at any age but rarely after the onset of menopause. Many are clinically insignificant and discovered accidentally. Occasional patient will present with a palpable pelvic mass, abdominal pain, or evidence of estrogenic activity such as precocious puberty in a child or menstrual irregularity in an adult due to endometrial hyperplasia.

The cyst is thin-walled, unilocular and may be single or multiple, unilateral or bilateral. They are usually small and only rarely exceed 5cm. The contents vary from serous through serosanguinous to clotted blood.


An inner layer of granulosa cells with uniform round nuclei and little cytoplasm lines follicle cysts and an inner layer of theca interna cells, which are small and spindle-shaped. The layers may be luteinized.

Clinical behavior

Most regress spontaneously.

  • Corpus luteum cysts

These are cystic dilatations of corpora lutea and result from delayed resolution of the central cavity of the corpus luteum. They are less common than follicle cysts.

Clinical appearances

These cysts are clinically insignificant but patients may present with irregular menses due to continued progesterone synthesis. The cyst is typically unilocular usually up to 5 cm in diameter with a convoluted yellow wall. The contents vary from serous or serosanguinous fluid to clotted blood.


The cyst wall is composed of an inner connective tissue layer, a middle layer of large luteinized granulosa cells and an outer layer of small, luteinized theca interna cells.

Clinical behavior

Usually self-limited with spontaneous regression.

  1. Multiple Cysts
  • Theca lutein cysts (Hyperreactio luteinalis)

These are multiple bilateral luteinized follicular cysts that occur most frequently with disorders causing increase serum human chorionic gonadotrophin levels such as pregnancy especially multiple gestation, hydatidiform mole, choriocarcinoma, fetal hydrops, exogenous hCG treatment, clomiphene treatment or polycystic ovary.

Clinical appearances

Abdominal symptoms are usually minimal. The condition may be detected as a pelvic mass during any trimester, at Cesarean section, or rarely immediately postpartum or after puerperium. Abdominal pain may result when there is hemorrhage into cyst, torsion with infarction or rupture with intra-abdominal hemorrhage occurs.

It is bilateral, usually causing moderately to massively enlargement of the ovaries, which contain multiple, thin-walled cysts filled with clear or hemorrhagic fluid. The cysts are rarely large.


The cysts show marked luteinization of the theca interna cells and, in some cases, the granulosa cells. The ovarian parenchyma is usually markedly edematous and frequently contains foci of luteinized stromal cells.

Clinical behavior

The condition usually involutes during the puerperium, postpartum period, following termination of the molar pregnancy, treatment of the choriocarcinoma or discontinuation of hCG or clomiphene therapy. However, this may take months to occur. Surgical intervention may be required to remove ruptured or infarcted tissue.

  • Polycystic Ovaries (Stein-Leventhal Syndrome)

Polycystic ovaries are characterized by bilaterally enlarged polycystic ovaries, chronic anovulation and clinical manifestations due to secretion of excess androgens. The initial abnormality resulting in the syndrome is not known but is believed to be related to hypothalamus-pituitary dysfunction leading to oversecretion of luteinizing hormone (LH). LH in turn stimulates the ovary to produce excess androgens. Secretion of follicle stimulating hormone (FSH) is inhibited resulting in repression of ovulation with follicle cyst formation.

Clinical appearances.

The usual clinical presentation is a young woman (between 15 and 30 years) with secondary amenorrhea, oligomenorrhea or irregular menses, infertility and hirsutism. About 50% exhibit virilism and 40% are obese. Other patients may be amenorrheic but otherwise normal.

Both ovaries are markedly enlarged and have a thickened, fibrotic capsule with smooth pearl-white surfaces.

Polycystic ovary showing the smooth pearl-white capsular surfaces. Cysts bulge out.


Microscopically, the outer portion of the cortex is thickened and fibrotic and many follicle cysts are present in the subcapsular cortex. The cysts have prominent outer theca interna layer, which is often luteinized. Corpora lutea are frequently absent due to the anovulation and occasional focal stromal luteinization is present. The chronic anovulation results in unopposed estrogenic stimulation of the endometrium leading to a variety of appearances ranging from mild atypical hyperplasia to well-differentiated endometrial adenocarcinoma.

Polycystic ovary with two subcapsular follicular cysts.

Clinical behavior

Treatment with drugs that either induce ovulation (clomiphene or hCG) or regulate the menstrual cycle restores fertility. Reduction of ovarian volume by wedge resection is also successful in initiating ovulation and restoring fertility. The endometrial changes including adenocarcinoma regress once ovulation is achieved.

  1. Miscellaneous Non-cystic conditions
  • Massive Ovarian Edema

This refers to tumor-like enlargement of one ovary, or occasionally both, due to accumulation of edema fluid in the stroma.

Clinical features

The condition typically occurs in young women who present with abdominal or pelvic pain, menstrual irregularities and abdominal distention. In some cases androgenic effects are seen. Partial or complete torsion occurs in approximately 50% of cases and about 75% are right sided.

The ovary involved is enlarged, soft, fluctuant and has a shiny, white, smooth surface. The cut surface shows a white, fibrotic and thickened superficial cortex, which appears like a capsule, and a solid, tan, homogeneous and gelatinous appearance with exudation of a watery fluid.

Massive ovarian edema. Swollen ovary with bulging cut surface.


There is marked diffuse stromal edema that separates follicles and their derivatives with sparring of the superficial cortex, which is thickened by fibrosis. Foci of luteinized stromal cells may be present.

Clinical behavior

This condition may be confused clinically with an ovarian neoplasm. It has no malignant potential. Most patients have been treated by oophorectomy but conservative management has been advocated for young patients.

  • Stromal hyperplasia

This condition is characterized by nonneoplastic proliferation of the ovarian stromal cells.

Clinical features

Stromal hyperplasia is most commonly seen in postmenopausal patients and may be associated with raised androgen levels and also with endometrial adenocarcinoma. Stromal hyperplasia is almost always bilateral, and may be associated with normal sized or enlarged ovaries. Cut surface shows a homogeneous white tissue replacing the ovarian parenchyma.


Microscopically, a diffuse proliferation of plump ovarian stromal cells within the cortex and medulla is seen.

  • Stromal hyperthecosis

This refers to luteinization of ovarian stromal cells not related to follicles.

Clinical features

The condition is most common in postmenopausal women in whom it is mild and clinically not significant. In young women of reproductive age, hyperthecosis produces virilization. These women are obese, hypertensive and have high insulin levels. In some cases estrogenic effects dominate with endometrial hyperplasia or well-differentiated endometrial adenocarcinoma. A few may show features characteristic of polycystic ovaries.

The ovaries are bilaterally involved and, in clinical cases, are enlarged. The capsule is smooth and cut surface is yellow.


Histologically, nests of luteinized stromal cells are present in the medulla and/or cortex.

Clinical behavior

The condition does not respond to clomiphene or wedge resection of the ovary. Oophorectomy halts progressive virilization and may also result in disappearance of the hypertension and hyperinsulinemia.

  • Endometriosis

See section on uterus.

Ovarian endometriosis.

Ovarian endometriosis. Many hemosiderin-laden macrophages are present.

Objectives Anat & Hist Nonneoplastic Lesions Neoplasms