From the Guidelines
Cysts are fluid-filled sacs that can form in various parts of the body, with several distinct types classified by location and characteristics, including epidermoid, sebaceous, ovarian, ganglion, Baker's, pilonidal, breast, renal, Bartholin's, and Tarlov cysts. The different types of cysts can be categorized based on their location and characteristics, such as:
- Epidermoid cysts, which appear as small bumps under the skin, containing keratin and often developing on the face, neck, or trunk 1
- Sebaceous cysts, which form from blocked oil glands, typically on the scalp, face, or back
- Ovarian cysts, which develop in or on the ovaries, ranging from functional cysts to pathological types like dermoid cysts containing tissue elements 1
- Ganglion cysts, which occur near joints or tendons, especially in the wrists and hands, containing synovial fluid
- Baker's cysts, which form behind the knee due to joint inflammation
- Pilonidal cysts, which develop near the tailbone, often containing hair and skin debris
- Breast cysts, which are fluid-filled sacs in breast tissue, commonly benign
- Renal cysts, which form in the kidneys and are usually harmless unless part of polycystic kidney disease
- Bartholin's cysts, which affect the Bartholin glands in women's genital area
- Tarlov cysts, which form on nerve root sheaths near the spine Most cysts are benign, though some require medical evaluation to rule out malignancy or address symptoms like pain, infection, or functional impairment, as supported by recent studies 1. It is essential to note that the management of cysts depends on their type, size, and location, as well as the patient's symptoms and medical history, and should be guided by the most recent and highest-quality evidence, such as the American College of Radiology's O-RADS US risk stratification and management system 1.
From the Research
Types of Cysts
- Epidermoid cysts: These are asymptomatic, dome-shaped lesions that often arise from a ruptured pilosebaceous follicle 2, 3, 4, 5. They can occur in hair-bearing and glabrous skin, as well as in oral mucosa and internal organs.
- Dermoid cysts: These are ectoderm-lined inclusion cysts that contain hair, sebaceous and sweat glands, and squamous epithelium 4. They differ from epidermoids in complexity and can occur in the orbit, calvarial diploic space, and intracranially.
- Teratomas: These are true neoplasms arising from misplaced embryologic germ cells 4. They contain a medley of heterogeneous tissues and can manifest prenatally or postnatally as a life-threatening mass.
- Intramuscular epidermal cysts: These are a type of epidermal cyst that can occur in the masticator space and may be misdiagnosed as a lymphatic malformation 5.
- Renal cysts: These can be benign or malignant and may require surgical exploration 6. The differentiation between benign and malignant renal cysts remains difficult, and radiological techniques may not be well suited for characterization.
Characteristics of Cysts
- Epidermoid cysts are typically asymptomatic and have a visible central punctum 2, 3, 5.
- Dermoid cysts can produce mild symptoms and may be complicated by rupture or infection 4.
- Teratomas can be biologically benign or malignant and may require surgical treatment 4.
- Intramuscular epidermal cysts can present with facial swelling and may be misdiagnosed based on preoperative MRI 5.
- Renal cysts can be asymptomatic or symptomatic and may require surgical exploration to determine malignancy 6.