Simultaneous cloacogenic carcinoma in dizygotic twins

Dizygotic twins developed cloacogenic carcinoma of the anus almost simultaneously. The patients, although separated from the time they were 20-years-old, had very similar life styles. There are several reports in the medical literature of synchronous tumors in mono and dizygotic twins. It is recommended that if a cancer diagnosis is made in one twin, the other undergo workup to exclude the presence of a tumor with similar histology. The establishment of state or national twin registries would provide valuable information regarding the role of genetic and environmental factors in the development of not only cancer but also of various nonmalignant disorders.