Chemical analysis of adnexal cyst fluid.
OBJECTIVE: The purpose of the study was to determine if adnexal cyst fluid glucose, protein, and lactate dehydrogenase (LDH) levels can discriminate between cancerous and noncancerous adnexal masses. METHODS: Intracystic fluid was aspirated from adnexal masses immediately after operative excision. Patient age and menopausal status, mass size, and cyst fluid specific gravity were recorded. Cyst fluid and intraoperative serum glucose, protein, and LDH levels were measured. Masses were grouped by histopathologic diagnosis. Cyst fluid chemical levels and cyst fluid/serum ratios were compared among and between the groups. RESULTS: Fifty-eight adnexal masses were analyzed: 15 nonneoplastic (group 1), 23 benign neoplastic (group 2), and 20 malignant (group 3). There were no significant differences among the groups with regard to patient age, menopausal status, or cyst fluid specific gravity. Cyst size (cm2) was significantly different among the three groups (P < 0.01), with the largest mean size found in the cancer group. No significant differences in cyst chemistries or cyst fluid/serum ratios were found between groups 1 and 2. Comparing groups 1 and 3, all values were significantly different (P < 0.05), with the greatest level of significance attained by comparison of cyst fluid LDH levels (P < 0.001). Groups 2 and 3 statistically differed in cyst fluid levels and cyst fluid/serum ratios of both protein and LDH, with the highest levels of significance achieved by comparisons of cyst fluid levels and ratios of LDH (P = 0.001 and P < 0.001, respectively). The cyst fluid LDH level was found to be the best single chemistry for distinguishing noncancerous (groups 1 and 2) from cancerous (group 3) adnexal masses. A cyst fluid LDH level of >/=451 U/L imparted a 90% sensitivity and 71% specificity for detecting malignancy. CONCLUSIONS: Evaluation of adnexal cyst fluid LDH may help to distinguish benign from malignant adnexal masses. More cases are needed to adequately assess the predictive value and clinical utility of this approach.