Adenocarcinoid of the appendix presenting with metastases to the liver

A case of hepatomegalia due to multiple metastases of unknown origin to the liver is described. At autopsy the primary tumor, an adenocarcinoid tumor of the appendix, was identified along with multiple metastases to the lymph nodes and widespread peritoneal carcinoidosis. Hepatic metastases from an appendiceal adenocarcinoid tumor has not been described previously. In the liver and lymph nodes the tumor had an insular growth pattern and was composed predominantly of cells of carcinoid type, whereas the carcinoidosis was composed almost entirely of signet-ring cells. It is suggested that differentiation of the metastases of appendiceal adenocarcinoids is modulated by factors in the recipient organ.