A cyst is a closed, sac-like structure that develops abnormally in body tissue, filled with air, fluid, or semi-solid material. These formations can occur virtually anywhere in the body, from the skin to internal organs like the ovaries or kidneys. While many cysts are discovered incidentally and remain harmless, the decision to leave a cyst untreated is complex, involving an assessment of its type, location, and internal characteristics. Ignoring a cyst can lead to outcomes ranging from natural resolution to life-threatening emergencies.
When Cysts Resolve Without Intervention
The most favorable outcome for an untreated cyst is spontaneous resolution, where the structure shrinks and disappears without medical intervention. This natural regression is common for certain types of cysts linked to normal bodily functions. Functional ovarian cysts, which form as part of the menstrual cycle, resolve on their own in 70% to 80% of cases, typically within one to three months.
Ganglion cysts, found near joints and tendons, also demonstrate a high rate of spontaneous resolution, with over 60% disappearing over time. Resolution often involves the gradual reabsorption of the cyst’s fluid contents back into the surrounding tissue. In some cases, a minor internal rupture allows the contents to be dispersed and metabolized by the body.
Acute Complications of Leaving Cysts Untreated
Leaving certain cysts unaddressed can lead to acute, sudden complications requiring immediate emergency medical care. One dangerous event is cyst rupture, which occurs when internal pressure or trauma causes the cyst wall to burst. If the cyst is hemorrhagic, rupture can lead to significant internal bleeding and shock.
Cysts containing irritant materials, such as a dermoid cyst filled with sebaceous fluid, can spill their contents into the abdominal cavity upon rupture. This spillage triggers an intense inflammatory response known as chemical peritonitis, resulting in severe, sudden abdominal pain.
A previously benign cyst can also become infected if bacteria enter the sac, transforming it into a painful abscess—a localized collection of pus and bacteria. If the infection is not drained promptly, it risks spreading into the bloodstream, a life-threatening condition called sepsis.
A severe complication specific to mobile internal organs is torsion, where the weight of a large cyst causes the organ to twist on its supporting ligaments. Ovarian torsion cuts off the blood supply to the ovary, leading to ischemia and tissue death, requiring immediate surgical intervention.
Progressive Symptoms and Functional Impairment
Beyond acute emergencies, a cyst left in place can grow steadily, causing chronic issues due to mass effect—the pressure exerted on surrounding tissues. Continued growth of an internal cyst can displace nearby organs, leading to a persistent feeling of fullness or discomfort. For example, a large ovarian cyst can press against the bladder, causing a frequent need to urinate, or compress the bowel, resulting in chronic constipation.
In the joints, an expanding ganglion cyst can press directly on an adjacent nerve. This nerve compression results in chronic pain, tingling sensations, or numbness that radiates down a limb.
In the kidney, a large renal cyst can obstruct the normal flow of urine, potentially leading to kidney swelling or gradual impairment of its function. The presence of a growing mass can significantly reduce quality of life through chronic pain or functional impediment to normal organ operation.
The Importance of Definitive Diagnosis and Monitoring
The most significant risk associated with ignoring a cyst is the possibility that it is not benign or that it is masking a malignancy. Diagnosis involves imaging techniques like ultrasound, CT scans, or MRI to characterize the cyst’s internal structure. A purely fluid-filled “simple” cyst with thin walls is considered low-risk, with a malignancy rate of less than 1%.
Cysts described as “complex” have features such as thick or irregular walls, internal septations, or solid components, which raise suspicion. For instance, a Bosniak Category IV renal cyst, defined by its complex features, carries a malignancy risk as high as 90% to 100%.
For cysts initially classified as benign, a management strategy known as “watchful waiting” is often employed to avoid unnecessary surgery. This protocol requires scheduled follow-up imaging, typically via ultrasound every few months, to monitor for changes in size or the development of complex features. By accurately classifying and monitoring the cyst, healthcare providers can safely manage most non-threatening formations while ensuring that suspicious lesions receive prompt surgical evaluation.