A cyst is a fluid-filled sac that can form in various tissues throughout the body. A septated cyst presents a complex internal architecture because it is divided by one or more internal walls, known as septa. This structural difference classifies the cyst as “complex” and guides a physician’s approach to monitoring and treatment.
Defining Septated Cysts
A septated cyst is distinguished by the presence of internal partitions, or septa, which divide the fluid-filled space into multiple compartments, making the cyst multilocular. This differs from a simple, unilocular cyst, which is a single, undivided sac of fluid. These septa are visible on medical imaging as linear structures crossing the cystic space.
The complexity of the cyst is directly related to the characteristics of these internal divisions. Radiologists classify the cyst structure based on the number and thickness of the septa. A cyst with a single, thin septum is considered less complex than one with multiple, thick, or irregular septa. Thin septations are generally defined as being less than three millimeters thick, while thicker septations suggest a more complex structure.
Common Sites and Detection Methods
Septated cysts can occur in many different organs, including the ovaries, kidneys, liver, and breasts. The most common location for these cysts in women is the ovary, where they are often found incidentally during routine pelvic imaging. In the kidneys, they may be identified during scans for unrelated abdominal issues.
Ultrasound is generally the first-line diagnostic tool used because it is highly effective at visualizing the fluid and the internal septations within the cyst. Other advanced imaging techniques, such as Computed Tomography (CT) scans and Magnetic Resonance Imaging (MRI), provide additional details. MRI offers superior contrast resolution, which is helpful for characterizing the contents of the cyst compartments and the thickness of the septa. These methods allow physicians to accurately measure the cyst’s size and assess its internal characteristics.
Clinical Significance of Internal Divisions
The presence of septations elevates a cyst from a simple finding to a complex one, requiring a more thorough investigation. While simple cysts are almost always benign, a complex, septated cyst carries a slightly higher potential for complications or malignancy. The degree of concern is proportional to the specific features of the internal divisions.
Physicians analyze the thickness of the septa; thin septations are generally considered a minor feature, but septa greater than a few millimeters are a major point of scrutiny. The presence of nodularity, which are small solid growths within the septa or cyst wall, is a concerning feature that prompts further evaluation.
Another factor is the presence of blood flow, or vascularity, within the septa, which is detected using color Doppler ultrasound. Vascularity suggests active tissue growth. These detailed imaging characteristics help physicians use risk stratification systems, like the Ovarian-Adnexal Reporting and Data System (O-RADS), to determine the likelihood of the cyst being benign or needing immediate intervention.
Treatment and Monitoring Pathways
Once a septated cyst is identified, the clinical management pathway is determined by assessing its risk features, size, and symptoms. For many small septated cysts that have only thin septations without solid components, the approach is often active surveillance. This involves a “wait-and-see” strategy with follow-up imaging, typically an ultrasound, performed every few months.
The goal of active surveillance is to monitor the cyst for changes in size or internal structure, as many benign cysts will resolve or remain stable over time. This conservative approach is common for asymptomatic, low-risk patients. Postmenopausal women with septated cysts generally require a more aggressive evaluation due to a higher baseline risk.
Intervention is usually reserved for cysts causing persistent pain or discomfort, or those with features suggesting a higher risk profile. Aspiration, which involves draining the fluid, may be an option for certain cysts. However, surgical removal is often recommended for large cysts or those with thick septations or solid components, with the goal of preserving surrounding organ tissue.