cyste

A cyst is a closed sac-like structure that can contain air, fluids, or semi-solid material. Cysts are typically lined by a membrane; when the lining is epithelial or endothelium, the lesion is called a true cyst. Cysts that lack such lining are referred to as pseudocysts. They can arise anywhere in the body and vary in size and complexity.

Cysts may be congenital or acquired and can result from developmental anomalies, infection, inflammation, injury, or blockages of ducts. They are common in the skin (such as sebaceous or epidermoid cysts), in the ovaries (functional cysts like follicular or corpus luteum cysts), kidneys (simple renal cysts), liver (simple hepatic cysts), and pancreas (pancreatic cysts and pseudocysts), as well as in the brain (arachnoid cysts).

Diagnosis is typically based on imaging, with ultrasound often serving as the first-line tool. Computed tomography (CT) or magnetic resonance imaging (MRI) may be used to further characterize a cyst and its relationship to surrounding structures. Fluid aspiration or biopsy may be performed if there is concern for infection or malignancy, or to obtain a precise diagnosis.

Management depends on symptoms, size, and features. Many cysts are asymptomatic and require no treatment. Symptomatic, enlarging, or complex cysts may be drained or surgically removed. Treatment options include percutaneous drainage, sclerotherapy, laparoscopic decortication or cystectomy, and, in the case of ovarian cysts, observation for functional cysts or surgical removal if persistent or suspicious. Prognosis is generally favorable for simple cysts, while complex cysts require careful evaluation for malignancy or complications.