Ovarian fibroma/fibrothecoma with elevated serum CA125 level

Abstract Ovarian fibroma/fibrothecoma with elevated serum OC125 antigen (CA125) is rarely encountered in clinical practice, and also easily misdiagnosed as epithelial ovarian carcinoma (EOC). The aim of this study was to investigate the clinicopathological features of ovarian fibroma/fibrothecoma with elevated serum CA125. In total, 580 patients who underwent primary surgery and pathologically diagnosed as ovarian fibroma/fibrothecoma were retrospectively analyzed. The clinicopathological parameters were collected and compared between the patients with elevated serum CA125 (>35 U/mL) and without. The immunoreactivity for CA125 in ovarian fibroma/fibrothecoma and epithelial cancer tissues was detected and compared by immunohistochemistry. Univariate and multivariate analyses were performed to identify factors associated with elevated serum CA125 level. The correlation between the immunoreactivity of CA125 in tissue and serum CA125 level was examined by Pearson correlation analysis. Elevated serum CA125 level (range 36.7–1848 u/m) was found in 66 of 580 (11.3%) ovarian fibroma/fibrothecoma patients. Univariate analysis showed that the elevated serum CA125 level was significantly correlated with tumor diameter ≥10 cm (P < .001), ascites (P < .001), and hydrothorax (P < .001). Multivariate analysis revealed that tumor diameter ≥10 cm and ascites were independently associated factors (P < .001 and < .001 respectively). Immunohistochemical staining showed that the expression of CA125 was negative in all fibroma/fibrothecoma tissues, but positive in all EOC tissues, and the immunoreactivity for CA125 was positively correlated with serum CA125 level in the EOC patients (P = .005). The elevated serum CA125 level in ovarian fibroma/fibrothecoma is nontumor originated and occurs more frequently in those with larger size tumor or Meigs syndrome.