Meigs Syndrome 

Meigs syndrome is defined as the triad of benign ovarian tumor with ascites and pleural effusion that resolves after resection of the tumor. The ovarian tumor in Meigs syndrome is a fibroma.

In 1934, Salmon described the association of pleural effusion with benign pelvic tumors. In 1937, Meigs and Cass described 7 cases of ovarian fibromas associated with ascites and pleural effusion.^[1] In 1954, Meigs proposed limiting true Meigs syndrome to benign and solid ovarian tumors accompanied by ascites and pleural effusion, with the condition that removal of the tumor cures the patient without recurrence. Histologically, the benign ovarian tumor may be a fibroma, thecoma, cystadenoma, or granulosa cell tumor.

Pseudo-Meigs syndrome consists of pleural effusion (an example of which can be seen in the image below), ascites, and benign tumors of the ovary other than fibromas. These benign tumors include those of the fallopian tube or uterus and mature teratomas, struma ovarii, and ovarian leiomyomas.^[2] This terminology sometimes also includes ovarian or metastatic gastrointestinal malignancies.

Atypical Meigs characterized by a benign pelvic mass with right-sided pleural effusion but without ascites has been reported at least twice. As in Meigs syndrome, pleural effusion resolves after removal of the pelvic mass.

Pseudo-pseudo Meigs syndrome includes patients with systemic lupus erythematosus and enlarged ovaries.^[3]

Etiology of ascitic fluid

The pathophysiology of ascites in Meigs syndrome is speculative. Meigs suggested that irritation of the peritoneal surfaces by a hard, solid ovarian tumor could stimulate the production of peritoneal fluid. Samanth and Black studied ovarian tumors accompanied by ascites and found that only tumors larger than 10 cm in diameter with a myxoid component to the stroma are associated with ascites.^[4] These authors believe that their observations favor secretion of fluid from the tumor as the source of the ascites.

Other proposed mechanisms are direct pressure on surrounding lymphatics or vessels, hormonal stimulation, and tumor torsion. Development of ascites may be due to release of mediators (eg, activated complements, histamines, fibrin degradation products) from the tumor, leading to increased capillary permeability.

Origin of pleural effusion

The etiology of pleural effusion is unclear. Efskind and Terada et al theorize that ascitic fluid is transferred via transdiaphragmatic lymphatic channels. The size of the pleural effusion is largely independent of the amount of ascites.

• Efskind's study: Efskind injected ink into the lower abdomen of a woman with Meigs syndrome and found that the ink particles accumulated in the lymphatics of the pleural surface within half an hour. Blockage of these lymphatics prevented accumulation of pleural fluid and caused an increase in ascitic fluid.
• Terada and colleagues' study: In 1992, Terada and colleagues injected labeled albumin into the peritoneum and found that the maximum concentration was detected in the right pleura within 3 hours.

Nature of the ascitic and pleural fluid

Ascitic fluid and pleural fluid in Meigs syndrome can be either transudative or exudative. Meigs performed electrophoresis on several cases and determined that pleural and ascitic fluids were similar in nature. Tumor size, rather than the specific histologic type, is thought to be the important factor in the formation of ascites and accompanying pleural effusion.

Frequency

United States

Ovarian tumors are more prevalent in upper socioeconomic groups. Ovarian fibroma is found in 2-5% of surgically removed ovarian tumors, and Meigs syndrome is observed in about 1%. Ascites is present in 10-15% of those with ovarian fibroma and hydrothorax in 1%, especially with larger lesions.

International

Prevalence is unknown.

Mortality/Morbidity

Although Meigs syndrome mimics a malignant condition, it is a benign disease and has a very good prognosis if properly managed. Life expectancy after surgical removal of the tumor mirrors that of the general population.

Age

The incidence of ovarian tumor begins to increase in the third decade and increases progressively to peak in the seventh decade. Meigs syndrome in prepubertal girls with benign teratomas and cystadenomas has been reported.