The implication of tumor biomarker CA19-9 in the diagnosis of intracranial epidermoid cyst

Object: The diagnosis of intracranial epidermoid cyst (IEC) relies solely on MRI, which is time and money consuming. The application of tumor biomarkers in IEC has never been systematically studied. Here we screened a group of commonly used tumor biomarkers to assess their diagnostic value in IEC. Results: Serum tumor biomarkers were assessed in 42 IECs and 42 paired healthy controls. Only serum CA19-9 level was significantly higher in the IEC group (median 20.3U/ml vs. 6.5U/ml, p < 0.001). Area under curve for CA19-9 was 0.806 (95% CI 0.700-0.912), with cutoff value of 13.15 U/ml (sensitivity 71.4%, specificity 97.6%). Tumor size was significantly different between CA19-9 positive and CA19-9 negative groups(64.14 +/- 67.91cm3 vs. 19.43 +/- 13.76 cm(3), p = 0.04) and linear regression analysis revealed a positive correlation. Neither the extent of resection nor recurrence rate showed any significant difference between the two groups. Methods: This is a retrospective study of IEC patients treated between 2009 and 2014. We analyzed the expression of common serum tumor biomarkers, including carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen, carbohydrate antigen125 and squamous cell carcinoma in both IEC and healthy control group. Receiver operating characterisitics curves were constructed to evaluate the diagnostic accuracy. Conclusions: Our data indicated that for serum CA19-9 level higher than 13.15U/ml, after excluding the possibility of gastrointestinal system tumor, lung cancer, inflammation and other related diseases, the existence of IEC should be considered. Further prospective study is needed to gain more understanding of the value of CA19-9 in postoperative evaluation and surveillance.