Meigs Syndrome
Definition
Meigs syndrome is a triad of medical conditions where there is a benign ovarian tumor (specifically an ovarian fibroma) with ascites (fluid accumulation in the abdominal cavity) and pleural effusion (fluid around the lungs in the pleural space). Once the tumor is removed, both ascites and pleural effusion resolves. The exact reason why fluid accumulation occurs in the abdomen and around the lung with a benign ovarian tumor is not fully understood although there are several theories. It tends to occur with an ovarian fibroma but is sometimes seen with other types of benign ovarian tumors and even malignancies. Overall Meigs syndrome is uncommon affecting only 1 out of 100 women with an ovarian tumor. When present, ascites is more commonly seen without a pleural effusion.
Pathophysiology
Benign tumors, although non-cancerous, can still cause a host of complications in the body beyond the organ where it originates. Most of these complications are a result of the mass pressing against blood vessels, lymphatics and nerves. Sometimes it is associated with abnormal hormone secretion or triggering reactions within the body for reasons that are not clearly obvious at the outset. Meigs syndrome is one such instance. Fluid accumulation occurs in the abdomen and around the lungs in the pleural space as a result of some disruption caused by a benign ovarian tumor. The exact mechanism behind this syndrome is not clearly understood.
Picture of ovarian fibroma (white mass) from Wikimedia Commons
It is believed that the fluid that accumulates around the lung (pleural effusion) originates from the abdomen. The cause of the abdominal fluid accumulation (ascites) has not been conclusively established. There are various hypotheses to explain this phenomenon. One hypothesis is that the fluid originates from the ovary itself as Meigs syndrome tends to arise with benign tumors larger than 10 centimeters (cm) in diameter with a central fluid-mucus collection. However, there are various other ways that the fluid accumulation may also occur. The tumor may press on blood vessels and lymphatics thereby preventing tissue fluid from draining away or allowing fluid to leak out of a vessel.
A tumor marker known as CA-125 is found to be elevated in Meigs syndrome although levels are lower than would be seen with cancerous tumors. The significance of this marker may be linked to the peritoneum rather than the ovary. It has also been proposed that the tumor may irritate the peritoneum thereby causing it to secrete copious amounts of fluid into the cavity or that hormonal changes and inflammatory mediators associated with the tumor may lead to edema.
Several studies have confirmed that the fluid within the abdomen in ascites is at least part of the fluid that accumulates around the lung in the pleural space (pleural effusion). Whether this fluid crosses the diaphragm to enter the pleural space or is carried by the lymphatics from the abdomen is unclear.
Symptoms
The symptoms of Meigs syndrome is a combination of the clinical presentation of a benign ovarian tumor, ascites and pleural effusion. The presenting symptoms and its intensity is dependent of the severity of each condition. Collectively these symptoms can sometimes be confusing but when considered as three separate conditions, its presence is better understood. At the outset the symptoms may be vague and Meigs syndrome is not clearly identified. Generalized symptoms such as fatigue may be present.
Benign Ovarian Tumor
- Pelvic mass.
- Menstrual irregularity.
- Cessation of periods (amenorrhea) in women who are approaching menopause,
Ascites
- Bloated sensation.
- Abdominal swelling apparent by the increase in girth.
- Weight loss is usually present in Meigs syndrome but severe ascites can cause weight gain.
Pleural Effusion
- Dry cough (non-productive meaning that there is no sputum or phlegm).
- Shortness of breath – in the early stages this only occurs with exertion.
- Decreased stamina.
Causes
Meigs syndrome occurs in the backdrop of benign ovarian tumors and specifically a fibroma. When the syndrome occurs with other types of benign ovarian tumors other than a fibroma, it is known as pseudo-Meigs syndrome. It may also include a pleural effusion and ascites with cancerous ovarian tumors and even conditions like systemic lupus erythematosus (SLE) with enlarged ovaries. Some of these conditions in pseudo-Meigs can have very severe and potentially life threatening outcomes.
Although there are several hypotheses about the pathophysiology (disease mechanism), the exact reason why ascites and pleural effusions occur with a benign ovarian tumor is unclear. It is also not known where the fluid originates from, whether from the tumor or ovary, or leaking from blood vessels or lymphatics. There are several studies to suggest that the fluid in the pleural effusion is common to a large extent with the the ascitic fluid. The characteristic feature of Meigs syndrome is resolution of the ascites and pleural effusion with removal of the tumor. Therefore the benign ovarian tumor plays a central role in the syndrome.
Diagnosis
Various diagnostic tests should be conducted for Meigs syndrome. One of the main reasons that these investigations should be undertaken is to exclude serious underlying causes other than the association with benign ovarian tumors. Ascites and pleural effusion can occur with a number of different conditions ranging from cancers to liver, heart and kidney failure. Investigations may include laboratory tests on blood and fluid samples as well as imaging studies. Some of these tests include :
- Blood – complete blood count, urea and electrolytes and CA125 levels.
- Abdominal and pelvic ultrasound, CT scan of the abdomen and pelvis and chest x-ray.
- Fluid collection from the abdomen (paracentesis) and pleural space (thoracentesis) or a Pap smear.
Treatment
Fluid aspiration from the cavities can be helpful. Both paracentesis and thoracentesis can be done for therapeutic reasons and not only as diagnostic procedure to collect fluid samples for testing. However, the condition may recur and therapeutic paracentesis and thoracentesis are done only to ease the symptoms of ascites and pleural effusion respectively. It is only necessary when the fluid accumulation is causing severe discomfort and leading to functional impairment. If minor, therapeutic paracentesis and thoracentesis may not be necessary.
Surgery
Ideally the ovarian tumor should be removed and in Meigs syndrome this will lead to complete resolution of the ascites and pleural effusion. Successful removal of the tumor is considered curative. Recurrence of ascites and pleural effusion following surgical removal of the tumor is uncommon.
Surgery may involve removal of the affected ovary with or without the fallopian tube on the affected side (oophorectomy or salpingo-oophorectomy) for women of reproductive age. The uterus may also be removed along with the ovaries and fallopian tubes on both sides in older women who have passed menopause. Healthy ovarian tissue is spared as far as possible in young girls who have not as yet reached puberty and wedge resection of the ovary may be conducted in these cases.
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