Ovarian cysts are common gynecological findings, involving fluid-filled sacs that develop on or within an ovary. While most are small and cause no symptoms, a cyst can occasionally grow large enough to impact surrounding structures. This presence of an internal pelvic mass may lead to discomfort felt in areas remote from the ovary, such as the leg.
The Mechanism Linking Ovarian Cysts to Leg Pain
The connection between an ovarian mass and leg pain is primarily a matter of physical proximity and nerve compression. The pelvis is a compact space where the ovaries lie close to major nerve pathways that travel into the lower extremities.
A growing ovarian cyst can exert direct pressure on these adjacent nerves, irritating them and triggering pain signals. The obturator nerve, which originates from the lumbar spine and provides sensation to the inner thigh, is particularly susceptible to compression from pelvic masses. Pressure on the obturator nerve can cause pain that radiates down the inner thigh or groin area.
The sciatic nerve is another element, supplying the back of the leg and foot. The sciatic nerve roots (L4-S3) are located in the pelvic area, and a large cyst positioned posteriorly can physically press against them. This compression can result in pain that mimics sciatica, characterized by a deep, aching, or shooting sensation that travels down the back of the leg. The pain is often unilateral, occurring only on the same side as the affected ovary and cyst.
Types of Cysts Most Likely to Cause Lower Body Pain
The size and type of the cyst are significant factors in determining if it will cause pain in the lower body. Small, functional cysts rarely grow large enough to compress nerves. These cysts typically resolve on their own within a few months without causing significant symptoms.
Cysts that reach a diameter greater than five centimeters are more likely to create pressure on surrounding structures and nerves. Pathological cysts, such as endometriomas (often called “chocolate cysts”) or cystadenomas, are frequent culprits because they tend to grow larger than functional cysts. Endometriomas, which are associated with endometriosis, can also cause inflammation that further irritates nearby nerves like the sciatic nerve. Dermoid cysts, which form from reproductive cells and can contain various tissues, may also grow to a size that causes compression and discomfort in the hip and leg.
Accompanying Symptoms of Ovarian Cysts
Leg pain is usually not an isolated symptom. A common complaint is a feeling of pelvic pressure or a dull ache in the lower abdomen, frequently on the side of the cyst. This pressure can lead to bloating or a sensation of fullness.
The cyst’s size and location can also interfere with the function of nearby organs like the bladder and bowels. This may result in a frequent need to urinate or difficulty emptying the bladder completely due to physical compression. Another element is pain during sexual intercourse, known as dyspareunia. Some individuals may also experience changes in their menstrual patterns, such as heavy, irregular, or unusually light periods.
Warning Signs: When Leg Pain Requires Emergency Attention
While dull, persistent leg pain due to nerve compression is a chronic symptom, a sudden change in pain intensity can signal an acute medical emergency. The first is ovarian torsion, which occurs when a large cyst causes the ovary to twist on its supporting ligaments, cutting off its blood supply. Ovarian torsion presents with sudden, severe, stabbing pain in the lower abdomen or pelvis.
This severe pain may radiate to the lower back, flank, and sometimes the thigh, often accompanied by nausea and vomiting. Another acute event is a cyst rupture. A ruptured cyst causes a sudden, intense onset of pelvic pain. If there is significant internal bleeding, it can lead to symptoms like dizziness, lightheadedness, or a rapid heart rate. Any sudden increase in leg pain intensity coupled with severe abdominal pain, nausea, or signs of shock necessitates immediate medical evaluation.