Colon carcinoma presenting as ovarian metastasis.

An adnexal mass is a common gynecological finding. Most adnexal masses are benign neoplasms, especially in premenopausal women. Yet, here we report a premenopausal woman with an adnexal mass that turned out to be an ovarian metastasis from colon cancer. This case emphasizes the importance of considering an ovarian metastasis in patients with (partially) solid adnexal masses and low serum CA125 levels. In addition, we identified the same KRAS mutation in the biopsied liver metastasis and resected right ovarian metastasis. This is in accordance with a previous molecular study of matched tumor pairs/trios of colorectal cancer patients with ovarian metastases, suggesting that mutated KRAS is a universal driver of the metastatic disease in women with KRAS-mutated colorectal cancer with ovarian metastases. More than half of all colorectal cancer patients with ovarian metastases harbor KRAS mutations. Future studies may investigate the efficacy of KRAS inhibitors in the treatment of these patients.