What is a cyst?
A cyst is a small sac-like structure that typically appears in many different parts or organs of the body. It is an enclosed pocket of fibrous tissue usually filled with fluid, air, or other substances [1]. Cysts can grow almost anywhere on the body or beneath the skin and are usually non-cancerous (benign) [1].
What are the causes of cysts?
Cysts can result from several causes. Some cysts are associated with an underlying condition – such as polycystic ovary syndrome. Others are formed when dead skin cells do not shed like they ought to. Cysts can also result from damage to hair follicles, clogging of the duct within the hair follicle, degeneration of connective tissue within a joint, and ovulation [2].
Infections, inherited diseases, genetics, chronic inflammation and duct blockages can also give rise to cysts and pseudocysts. [1] Liver cysts can be caused by a malformation in the bile ducts (what is known as biliary cysts), but it is not yet well understood why it happens, and some people remain asymptomatic (without symptoms) all their lives. In others, it only appears towards the end of life or in the middle of life. They can also occur with a parasite from the genus echinococcus, which causes cysts in various organs, including the liver [3].
Kidney cysts result from many conditions, with various clinical characteristics and different prognoses. Some cyst proteins have been identified and localised in the centrosome complex (CCC) [4].
Risk factors of cysts
Cysts can develop in various parts of the body, and their risk factors can vary depending on their location and type.
A risk factor for earlobe cysts can be a rare syndrome or genetic disorder, past puberty, acne or a history of acne, or an injury of the skin that stimulates cells to grow or react anomalously [5].
Pancreatic cysts may be related to genetic diseases, such as Von Hippel-Lindau disease, chronic pancreatitis, gallstones, heavy alcohol use and abdominal injury.
Kidney cysts are more common in people over 50 years of age and in men than in women. Smoking and hypertension can also increase the risk of kidney cysts, as can a genetic predisposition such as polycystic kidney disease [7].
The epidermal growth factor receptor (EGFr) in the cyst fluids acts as a mediator, increasing the risk of breast cysts in apocrine metaplasia or epithelial hyperplasia [8].
Follicular cysts occur more commonly in women of childbearing age. They might be caused by having had an ovarian cyst in the past, having irregular menstrual cycles, taking fertility drugs, having too much estrogen or insulin in the body, being overweight, and being stressed [9].
Follicular cysts of the ovary after menopause occur because of the level of oestrogen in an individual’s body, which can be the culprit in severe pelvic infection, polycystic ovary syndrome (PCOS), endometriosis, hypothyroidism and smoking cigarettes [10].
Liver cysts are more prevalent in the elderly and men, and they can be influenced by renal dysfunction and hypertension [11].
Where on the body do cysts most likely appear?
Cysts can occur throughout the body, but, like all other lesions, they sometimes prefer specific locations. Breast cysts are generally found in the upper outer quadrant or the central margins of the breast [12]; another type of common cyst, known as an epidermal cyst, is often found on the scalp, face, trunk, neck and extremities [13].
Cystic lesions, or epidermal cysts, occur more often in the head and neck and most commonly in the oily face skin in patients with acne [14]. Out of one million epidermoid tumours (or cysts), 80% emerge from the ovaries and testicles, about 7% in the head and neck, and 1.6% of cases in the oral cavity [15].
Hydatid cysts are due to infection with a tapeworm, especially in the liver and lungs. Yet other organs, notably those containing highly vascularized tissues such as:
- The brain
- Muscle
- Heart
- Pancreas
- Adrenal gland
- Thyroid gland [16, 17].
Lymphangiomas, the most common primary tumours of the lymphatic system, occur most frequently in the neck (75%) and axillae (20%) but can also arise in the:
- Mesentery
- Retroperitoneum
- Mediastinum
- Omentum
- Colon
- Pelvis
- Groin
- Bone
- Skin
- Scrotum
- Spleen [18].
Can I have a cyst on my bikini line?
Yes, you can have a cyst along your bikini line. A cyst is a balloon-shaped sac of solid or fluid material under the skin that can form anywhere along your bikini line [19]. However, razor burns and small bumps resembling acne, called folliculitis, are not cysts [19].
The two most frequent types of cysts typically found beneath the skin are sebaceous (pilar) cysts and epidermoid cysts. Pilar cysts are filled with thick white or yellow fluids, and epidermoid cysts with keratin (which is typically yellow) [19].
Pubic cysts are usually caused by trapped hair, oil or skin debris and tend to happen in the bikini line area. They occur frequently after people remove their pubic hair at home, leaving hairs that grow back in a bent position. The entrapped hairs can turn into ingrown hairs, which may, in turn, develop into cysts. Not every ingrown hair turns into a cyst [19].
A cyst in your bikini area can become infected, mainly if it breaks the surface and you try to pick at it or gets caught on clothing and rubbed raw. Symptoms of an infected cyst include redness of the bump itself, red streaks that come off the bump, pain or tenderness, and pus or some other kind of muck coming out of the bump [19].
Ask your doctor to treat your bikini line cyst if it is bothersome. Many skin cysts in your bikini line may eventually shrink or disappear on their own without treatment. Smaller and less inflamed cysts may be treated with prescription steroid creams. Very infected bikini line cysts may require oral antibiotics [19].