Angina, also known as angina pectoris, is chest pain or pressure, usually caused by insufficient blood flow to the heart muscle (myocardium). It is most commonly a symptom of coronary artery disease.Angina is typically the result of obstruction or spasm of the arteries that supply blood to the heart muscle. The main mechanism of coronary artery obstruction is atherosclerosis as part of coronary artery disease. Other causes of angina include abnormal heart rhythms, heart failure and, less commonly, anemia. The term derives from the Latin angere ("to strangle") and pectus ("chest"), and can therefore be translated as "a strangling feeling in the chest". The severity of angina pain does not always match the degree of oxygen deprivation to the heart or the risk of a myocardial infarction (heart attack). Some people may experience severe pain even though there is little or no risk of a heart attack. Others may have a heart attack and experience little or no pain. In some cases, angina can be quite severe. Worsening angina attacks, sudden-onset angina at rest, and angina lasting more than 15 minutes are symptoms of unstable angina (usually grouped with similar conditions as the acute coronary syndrome). As these may precede a heart attack, they require urgent medical attention and are, in general, treated similarly to myocardial infarction.In the early 20th century, severe angina was seen as a sign of impending death. However, modern medical therapies have improved the outlook substantially.
They are generally mobile masses that can consist of:

Fibrous tissues and fluids
A fatty (keratinous) substance that resembles cottage cheese, in which case the cyst may be called "keratin cyst" - this material has a characteristic "cheesy" or foot odor smell
A somewhat viscous, serosanguineous fluid (containing purulent and bloody material)The nature of the contents of a sebaceous cyst, and of its surrounding capsule, differs depending on whether the cyst has ever been infected. With surgery, a cyst can usually be excised in its entirety. Poor surgical technique, or previous infection leading to scarring and tethering of the cyst to the surrounding tissue, may lead to rupture during excision and removal. A completely removed cyst will not recur, though if the patient has a predisposition to cyst formation, further cysts may develop in the same general area. Causes
Cysts may be related to high levels of testosterone, hence may be more frequent in users of anabolic steroids.A case has been reported of a sebaceous cyst being caused by the human botfly.Hereditary causes of sebaceous cysts include Gardners syndrome and basal cell nevus syndrome. Types
Epidermoid cyst
Pilar cyst
About 90% of pilar cysts occur on the scalp, with the remaining sometimes occurring on the face, trunk, and extremities. : 1477  Pilar cysts are significantly more common in females, and a tendency to develop these cysts is often inherited in an autosomal dominant pattern. : 1477  In most cases, multiple pilar cysts appear at once. : 1477

Treatment
Sebaceous cysts generally do not require medical treatment.