Objective The objectives were to evaluate the risk of malignant adnexal tumors in women with nongynecologic malignancies and to identify variables associated with the risk of malignant adnexal tumors.

Methods The eligibility criteria included the diagnosis of a nongynecologic malignancy and adnexal tumors, which were resected or subjected to biopsy at our institute between 1999 and 2010. The risk of malignant adnexal tumors was assessed by dividing the number of patients with metastatic tumors to the adnexa or primary adnexal cancers by the total number of patients. The association of clinicopathologic variables with the risk of malignant adnexal tumors was evaluated using the Fisher exact test and binary logistic regression analysis. In patients with metastatic tumors to the adnexa, the association of clinicopathologic variables with overall survival after adnexal surgery was examined using the log-rank test.

Results In 166 patients with adnexal tumors, 41 benign tumors, 113 metastatic tumors to the adnexa, and 12 primary adnexal cancers were diagnosed. Age older than 46 years, a tumor type associated with a high risk for malignant adnexal tumors, and bilateral tumors significantly increased the risk of malignant adnexal tumors. The overall survival of the patients with stomach cancer was significantly worse than the patients with colorectal or breast cancers.

Conclusion One hundred twenty-five of the 166 patients with nongynecologic malignancies who had adnexal tumors managed surgically were shown to have malignant tumors, and most of the tumors were metastatic from primary sites. The risk of malignant adnexal tumors was associated with age, nongynecologic malignancy, and bilaterality.