Cyst
Classification and external resources
Micrograph of a mediastinal bronchogenic cyst. H&E stain.
MedlinePlus	003240
MeSH	D003560

A cyst is a closed sac, having a distinct membrane and division compared to the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.

Types [edit]

• Acne cyst – Pseudocysts associated with cystic acne. Actually an inflammatory nodule with or without an associated epidermoid inclusion cyst.
• Aneurysmal bone cyst - Aggressive lesion with radiographic cystic appearance^[1]
• Arachnoid cyst (between the surface of the brain and the cranial base or on the arachnoid membrane)

• Baker's cyst or popliteal cyst (behind the knee joint)
• Bartholin's cyst
• Breast cyst
• Buccal bifurcation cyst^[2]
• Calcifying odontogenic cyst
• Chalazion cyst (eyelid)
• Chocolate cyst of ovary
• Choroid plexus cyst (brain)
• Colloid cyst
• Cysticercal cyst - the larval stage of Taenia sp. (Crain's backs)
• Dentigerous cyst (associated with the crowns of non-erupted teeth)
• Dermoid cyst (ovaries, testes, many other locations from head to tailbone)
• Epididymal cyst (found in the vessels attached to the testes)
• Ganglion cyst (hand/foot joints and tendons)
• Glandular odontogenic cyst
• Glial cyst (in the brain)
• Gartner's duct cyst (vaginal or vulvar cyst of embryological origin)
• Hydatid cyst (larval stage of Echinococcus granulosus (tapeworm))
• Hydrocele (testicle)
• Keratocyst (in the jaws, these can appear solitary or associated with the Gorlin-Goltz or Nevoid basal cell carcinoma syndrome. The latest World Health Organization classification considers Keratocysts as tumors rather than cysts)
• Liver cystic disease
• Meibomian cyst (eyelid)
• Mucoid cyst (ganglion cysts of the digits)
• Mucous cyst of the oral mucosa
• Nabothian cyst (cervix)
• Nasolabial duct cyst
• Odontogenic cyst (teeth)
• Ovarian cyst (ovaries, functional and pathological)
• Pancreatic cyst
• Paradental cyst
• Parapelvic cyst (kidney)^[3]
• Paratubal cyst (fallopian tube)
• Periapical cyst - This cyst, also known as radicular cyst, is the most common odontogenic cyst
• Pericardial cyst^[4]
• Peritoneal cyst (lining of the abdominal cavity)
• Pilar cyst (cyst of the scalp)
• Pilonidal cyst (skin infection near tailbone)
• Renal cyst (kidneys)
• Polycystic ovary syndrome
• Pineal gland cyst
• Radicular cyst - associated with the roots of non-vital teeth, also known as periapical cyst
• Residual cyst
• Sebaceous cyst - sac below skin
• Spermatocele (testicle)
• Stafne static bone cyst (An anatomic variant with radiographic cystic appearance in the posterior mandible)
• Tarlov cyst (spine)
• Trichilemmal cyst – Same as a pilar cyst. A familial cyst of the scalp.
• Vocal fold cyst

Cystic fibrosis [edit]

Despite being described in 1938 as the microscopic appearance of cysts in the pancreas,^[5] cystic fibrosis is an example of a genetic disorder whose name is related to fibrosis of the cystic duct and does not involve actual cysts.^[6]

Cystic neoplasm [edit]

Most cysts in the body are benign (dysfunctional) tumors, the result of plugged ducts or other natural body outlets for secretions. However sometimes these masses are considered neoplasm:

• Dermoid cyst
• Keratocystic odontogenic tumor
• Calcifying odontogenic cyst

Treatment [edit]

Treatment ranges from simple enucleation of the cyst to curettage to resection. There are cysts, e.g. buccal bifurcation cyst with self-resolation nature, in which close observation only can be employed unless the cyst is infected and symptomatic.^[2]

Related structures [edit]

A pseudocyst is collection without a distinct membrane.

A syrinx in the spinal cord or brainstem is sometimes inaccurately referred to as a cyst.

See also [edit]

• List of cutaneous conditions

References [edit]

External links [edit]

• "Cyst Symptoms and Causes" by Melissa Conrad Stöppler, MD and William C. Shiel, Jr., MD, FACP, FACR.