The characteristic features of Meigs' syndrome include the triad of - benign ovarian tumor, ascites (accumulation of fluid in the abdomen) and pleural effusion (accumulation of excessive fluid just outside the lungs). The pleural effusion usually resolves when the tumor is resected.
In most cases of Meigs' syndrome, the type of ovarian tumor is a fibroma and in cases where the tumor is of a different type like thecoma, cystadenoma, or a granulosa cell tumor, it is referred to as "pseudo-Meigs’ syndrome". This condition is usually present in those with systemic lupus erythematosus.
The cause of Meigs' syndrome does not appear to be clear although there seems to be an inflammatory reaction that causes the ascitis and pleural fluid accumulation.
A study carried out on ovarian tumors with ascites revealed that only large tumors (>10 cm in diameter) with a myxoid component caused ascites, as it favored secretion of fluid from the tumor. The tumor marker, CA-125, is elevated in Meigs’ syndrome but not up to a level found in malignancy.
Meigs' syndrome accounts for approximately 1% of all ovarian tumors. It usually occurs after the age of 40 years, with the frequency increasing with each added year. However, there are some rare reports about these tumors being present in girls of pre-pubertal age too.