Collision metastasis of breast and ovarian adenocarcinoma in axillary lymph nodes: a case report and review of the literature.

Despite their accepted clinical and genetic association, the incidence of synchronous breast and ovarian carcinoma is rare. Moreover, collision metastasis from both breast and ovarian carcinomas to the same lymph node, to our knowledge has never been reported. Review of the literature revealed eleven cases of metastatic malignant tumors colliding in the same lymph node, none of which had both ovarian and breast carcinoma. Our case was that of a 63 year old woman presenting with a breast lump that was diagnosed as infiltrating ductal carcinoma after a needle biopsy. One month later the patient was found to have malignant ascites, omental carcinomatosis and an ovarian mass. Histology and immunohistochemistry revealed high grade serous papillary adenocarcinoma. When surgery was done to treat the breast tumor some of the axillary lymph nodes revealed metastases from the breast primary, others metastases from the ovarian primary and one had both tumors in a collision phenomenon. Immunohistochemistry was used to confirm this finding.