Difference Between Cyst and Abscess

Though both abscess and cyst are sac like structures containing fluids enclosed by walls, abscess forms due to an infection or a foreign body, and cyst forms spontaneously. However, if a cyst is infected, it can easily turn into an abscess. Ultrasonically both look the same. This article will talk about both in detail highlighting their clinical features, causes, prognosis, and also the course of treatment abscess and cyst require.

What is Abscess?

Abscess is a sequel of acute inflammation. Infections and foreign bodies may cause an abscess. Acute inflammation is the body’s reaction to injurious agents. Acute inflammation features dilatation of blood vessels, increased capillary permeability, and fluid exudation. Blood cells also exit the circulation at inflamed sites. This is known as cellular exudation. Various chemicals secreted by bacteria attract these white blood cells to the infection site. This is called chemotaxis. Neutrophils in bacterial infections, eosinophils in parasitic infections and lymphocytes in viral infections reach the inflamed site in abundance. These cells secrete toxic substances that damage the causative bacteria. Oxygen free radicals, peroxides, superoxides, and digestive enzymes damage the surrounding host tissues, as well as invading bacteria, causing massive cell breakdown. Neutrophils remove the cellular debris. When the infection is virulent there is extensive tissue damage. When the infection is persistent or virulent, there is continuous pus formation. Dead and dying neutrophils, organisms, cell debris, and fluid exudate are collectively known as pus. Fibrous tissue walls the pus off. This enclosed space filled with pus is called an abscess.

What is a Cyst?

Cyst is a fluid filled cavity with a wall. Cysts can occur anywhere in the body. Ovarian cysts, pseudo-pancreatic cysts, vaginal wall cysts, fallopian tube cysts are a few common cysts. Fluid in the cysts does not contain a high protein amount. Cysts forms because of excessive accumulation of fluid. Ovary has a lot of follicles which absorb fluid and become graffian follicles. Graffian follicle contains a fluid filled cavity. When ovulation does not occur, the follicle continues to absorb fluid, and cyst forms.

In the pancreas, when the outflow ducts are blocked, secretions accumulate in the glandular parts, to give rise to cyst. There are benign and malignant cysts. Malignant cysts form due to cancerous cells. When there are cancer cells, almost always there is excessive secretion of fluid, and cysts are the end result. Malignant cysts contain multiple thick half walls inside the cavity partially dividing it into compartments. The outer wall of malignant cysts is normally very vascular. The outer wall may have irregular protrusions. Some malignant cysts secrete specific markers that can be used in the assessment. Malignant epithelial cysts in ovary secrete a chemical called CA-125. Serum CA-125 level is above 35 in malignant cysts.

What is the difference between Abscess and Cyst?

• Cysts form due to excessive fluid secretion while abscess form due to persistent ongoing tissue damage.

• Cyst wall is usually made up of surrounding normal tissue while fibrous tissue makes up the abscess wall.

• There is no regional inflammation in cysts unless infected while abscesses cause regional inflammation.

• Fluid inside cysts has low protein content while abscesses contain pus which is protein rich.

• Cysts disappear spontaneously while abscesses need drainage to accelerate healing.

• Antibiotics promote healing by killing off injurious microorganisms while cysts do not need antibiotics unless infected.