Types of Ovarian Cysts: A Plain-Language Guide

“Ovarian cyst” is a broad description, not one diagnosis. Some cysts form during normal ovulation and commonly disappear without treatment. Others develop from different ovarian tissues, are associated with conditions such as endometriosis, or arise beside rather than within an ovary.

Knowing the likely type helps a healthcare professional decide whether a cyst can be observed, needs follow-up imaging, or requires additional evaluation. The assessment usually considers ultrasound appearance, size, symptoms, age, menopausal status, and change over time.

Two Main Ways Ovarian Cysts Are Described

Cysts may be grouped by how they develop and by how they look on imaging. These systems overlap, but they are not identical.

Development or origin: Examples include functional cysts, endometriomas, dermoid cysts, and cystadenomas.
Imaging appearance: A report may describe a cyst as simple, hemorrhagic, complex, unilocular, multilocular, or as containing solid components.

An imaging description does not always identify the exact biological type. A radiologist may suggest a likely diagnosis while recommending follow-up or further testing.

Functional Ovarian Cysts

Functional cysts develop as part of the menstrual cycle. They are the most common ovarian cysts in people who ovulate, are generally benign, and often resolve naturally.

Follicular Cysts

An egg develops inside a follicle during the menstrual cycle. A follicular cyst can form when the follicle does not rupture and release the egg. Fluid remains inside, and the follicle may continue to enlarge.

Many follicular cysts cause no symptoms and disappear without treatment. Follow-up depends on their size, appearance, symptoms, and the individual situation.

Corpus Luteum Cysts

After a follicle releases an egg, it becomes a temporary structure called the corpus luteum. If fluid or blood collects inside it, a corpus luteum cyst can develop.

These cysts often resolve on their own. Some can cause pelvic discomfort or bleeding, and a ruptured corpus luteum cyst can occasionally require urgent evaluation.

Hemorrhagic Cysts

A hemorrhagic cyst is a cyst that contains blood, often because bleeding occurred within a functional cyst. Its ultrasound appearance can look complex even though the finding is frequently benign.

Symptoms and follow-up vary. Sudden severe pain, faintness, weakness, or signs of significant bleeding require prompt medical assessment.

Endometriomas

Endometriomas are ovarian cysts associated with endometriosis. Endometriosis occurs when tissue similar to the lining of the uterus grows outside the uterus. When it involves an ovary, repeated bleeding can contribute to formation of an endometrioma.

Endometriomas may be associated with pelvic pain, painful periods, pain during intercourse, or fertility concerns, although symptoms vary. They do not behave like ordinary functional cysts and may persist.

Management depends on symptoms, cyst appearance and size, age, reproductive plans, and other individual factors. Monitoring, medication for endometriosis symptoms, or surgery may be considered in different circumstances.

Dermoid Cysts

Dermoid cysts are also called mature cystic teratomas. They develop from germ cells, which can form different types of tissue. A dermoid cyst may therefore contain fat, hair, skin, calcification, or other material.

Most mature cystic teratomas are benign. Unlike functional cysts, they generally do not disappear during a menstrual cycle. Some grow slowly and may increase the risk of ovarian torsion, particularly as they become larger.

The appropriate approach depends on symptoms, size, imaging findings, age, and other medical considerations.

Cystadenomas

Cystadenomas develop from epithelial tissue associated with the ovary. They may contain thin, watery fluid or thicker mucus-like material and may be described as serous or mucinous.

Many cystadenomas are benign, but some can become large and cause pressure, bloating, discomfort, or complications. Imaging cannot always establish the precise diagnosis, so persistent or unusual findings may require additional evaluation.

Paraovarian and Paratubal Cysts

A paraovarian or paratubal cyst develops beside the ovary or fallopian tube rather than inside the ovary itself. Because it is located in the adnexa—the area containing the ovaries, fallopian tubes, and nearby tissues—it may initially be described as an ovarian or adnexal cyst.

Many are benign and found incidentally. Symptoms, size, growth, and imaging appearance determine whether observation or treatment is appropriate.

Simple and Complex Cysts

“Simple” and “complex” describe ultrasound appearance rather than one specific cause.

Simple Cysts

A simple cyst usually appears as a smooth, thin-walled sac containing clear fluid. It generally has no internal partitions or solid tissue. Many simple cysts—especially those related to ovulation—are benign.

Complex Cysts

A complex cyst contains something in addition to clear fluid. Ultrasound may show blood, internal echoes, septations, nodules, thick walls, or solid-appearing tissue.

Complex does not mean cancer. Hemorrhagic cysts, endometriomas, and dermoid cysts can all appear complex. Nevertheless, some complex features require closer evaluation because the complete imaging pattern matters.

For a fuller explanation, read our guide to complex ovarian cysts.

Benign, Borderline, and Malignant Masses

Most ovarian cysts are benign, but not every ovarian mass is a harmless functional cyst. Some epithelial tumors may be classified as benign, borderline, or malignant after specialist evaluation and, when surgery is performed, examination by a pathologist.

No single symptom, ultrasound word, or blood-test result can determine the diagnosis by itself. Concern is assessed using the overall pattern, including imaging findings, age, menopausal status, symptoms, growth, examination, and selected laboratory results.

Ovarian Cysts and PCOS Are Not the Same

Polycystic ovary syndrome, or PCOS, is a hormonal and metabolic condition. Despite its name, it is not the same as having one or more ordinary ovarian cysts.

Ultrasound may show many small follicles in someone with PCOS, but diagnosis is based on a broader combination of features. A person can have an ovarian cyst without having PCOS, and someone with PCOS can develop an unrelated ovarian cyst.

Why the Type Matters

The likely cyst type affects what happens next:

Some functional cysts can be monitored because they commonly resolve.
Persistent cysts may need repeat imaging or further characterization.
Endometriomas may be evaluated in the context of endometriosis symptoms and fertility plans.
Dermoid cysts and cystadenomas generally do not disappear like functional cysts.
Concerning or indeterminate masses may require specialist assessment.

Management should never be based on the cyst’s name alone. Size, symptoms, appearance, change over time, age, and menopausal status remain important.

How the Likely Type Is Determined

Pelvic ultrasound is commonly used to evaluate an ovarian cyst. It can show location, measurements, fluid, internal echoes, partitions, solid components, and blood flow. Comparison with an earlier examination can show whether a finding is resolving, stable, or growing.

Depending on the circumstances, a healthcare professional may recommend pregnancy testing, selected blood tests, repeat ultrasound, MRI, specialist consultation, or surgery.

Read more about how ovarian cysts are diagnosed and how to understand common terms in an ovarian cyst ultrasound report.

When to Seek Urgent Medical Care

Seek urgent medical evaluation for sudden, severe pelvic or abdominal pain—especially if it occurs with nausea, vomiting, fever, faintness, marked weakness, rapid breathing, or heavy bleeding.

These symptoms can have several causes. In someone with an ovarian cyst, they may require evaluation for complications such as cyst rupture, internal bleeding, or ovarian torsion.

The Bottom Line

Ovarian cysts include several different findings. Functional cysts develop with ovulation and often resolve. Endometriomas, dermoid cysts, cystadenomas, and paraovarian cysts develop for different reasons and may follow different courses.

Ultrasound appearance helps narrow the possibilities, but the appropriate interpretation depends on the complete clinical picture. A qualified healthcare professional can explain which type is suspected and whether monitoring, additional testing, or treatment is appropriate.

Medical Sources

Editorial note: This article was created with AI-assisted research and drafting. Medical claims were compared with the sources listed above. It has not been reviewed by a clinician.

Medical disclaimer: This website provides general educational information and is not a substitute for professional medical advice, diagnosis, or treatment. Contact a qualified healthcare professional with questions about symptoms, imaging results, diagnosis, or treatment.

This page is for general education and cannot diagnose a condition or replace care from a qualified healthcare professional.