The unique features of the presented case can be summarized as follows: a massive leiomyoma with the “digested” greater omentum and an elevated CA125 level accompanied by pseudo-Meigs syndrome. Uterine leiomyoma is the most common benign gynecological neoplasm . However, elevated CA125 levels, a massive leiomyoma and large ascites, which is collectively known as pseudo-Meigs syndrome, are rarely seen in this condition [11–14, 17–20]. In addition, no agreement on the pathogenesis of this rare condition has been established.
In this case, the increased abdominal circumference was considered to have resulted from pleural effusion and ascites. The pathogenesis of ascites in pseudo-Meigs syndrome is still not well defined . According to several hypotheses, the release of inflammatory cytokines and growth factors may cause vascular permeability [22–24]. An imbalance among arterial flow, venous drainage and direct pressure of the mass itself on lymphatic vessels may have caused the accumulation of nearly 5 L of ascites fluid in this case .
Removal of the large leiomyoma could resolve the ascites, but it is difficult to perform a complete excision when a leiomyoma is broadly adhered to adjacent structures. Full preparation, including detailed information about the size of the mass and its properties, could help in the design of a better surgical strategy . Specifically, various imaging techniques, including CT and MRI, were used in this case, and both modalities indicated an 18-cm mass with abdominal edema.
CTA confirmed an abundant blood supply from the mass. During the surgery, distended blood vessels from the omentum (top), uterus (bottom) and colon (lateral) were observed and carefully ligated. Notably, the uterovesical peritoneal reflection was lifted, which was evidently due to the massive leiomyoma. Thus, preparations should have been made to reduce the risk of injury and to prevent uncontrolled bleeding or incomplete resection. Therefore, we performed abdominal aortic balloon catheter placement before surgery .
The elevated CA125 level is another complicating factor in this case. It is well known that as a high molecular weight glycoprotein, CA125 is expressed in a substantial proportion of ovarian cancers . It has been reported that the serum CA125 levels range from 20 to over 1,000 IU/ml in patients with leiomyomas [29–31]. Due to the significant overlap between malignancies and myomas, CA125 failed to provide a potential benefit for differential diagnosis . The destruction of the peritoneum and severe adhesions of the omentum could explain why CA125 was overexpressed before surgery and reduced after surgery [33–34].
A preoperative diagnosis of a pelvic mass with pseudo-Meigs syndrome remains very challenging, especially in cases such as the one presented in this study. In these cases, an accurate diagnosis may only be made after surgery. For oncological safety, patients with myomas may undergo hysterectomy or ovariectomy, which impair reproductive function. On the contrary, an overly optimistic presumption of a benign leiomyoma may lead to the intra-abdominal spread of an unexpected sarcoma, which could result in poor survival. Therefore, it is always important to consider a broad differential diagnosis and employ the necessary scrutiny using imaging techniques. Uterine sarcomas are rare gynecological neoplasms, and some researchers believe that sarcomas originate from benign leiomyomas because they contain the same epithelial progenitor cells . Currently, no diagnostic technique is available to accurately distinguish this neoplasm. A meta-analysis revealed that expression of CA125, LDH and GDF-15 proteins is altered in sarcomas and that their serum levels are statistically higher . In our case, the CA125 level was elevated. However, we interpreted this finding and believed the higher level was due to the implantation of the leiomyoma on the omentum rather than as a cancer-related signal. Deficiency of LDH and GDF-15 levels was not assessed in our case. In addition, MRI may help in the preoperative distinction of sarcomas from benign leiomyomas . In our case, MRI revealed no swollen lymph nodes. However, the abundant blood supply to the mass observed on CTA imaging still roused our suspicion of a malignancy. Adenomyosis is another differential diagnosis of leiomyoma. A recent study has shown that MRI and elevated CA125 levels are fairly accurate for the diagnosis of adenomyosis, with a high sensitivity and specificity . A mean serum CA125 level of 19 U/ml has been established as the cutoff value. We speculated that this cutoff did not apply to our case because of the size of the mass and the tight adhesion. Preoperative MRI revealed a suspected abdominopelvic mass with large ascites, which did not support the diagnosis of adenomyosis.
In conclusion, we have presented an unusual case of pseudo-Meigs syndrome with a uterine leiomyoma and an elevated CA125 level. CTA was used for the detection and ligation of the parasitic blood supply (in this case, mainly the blood vessels of the greater omentum). Surgeons should be aware of the malignant potential of this tumor and plan for the optimal surgical procedure, which would lead to a more appropriate treatment strategy.