Multiple Primary Cancers with Microsatellite Instability: Report of a Case

We report here a patient who developed a variety of tumors both synchronously and metachronously over a 2‐year period. The involved organs were the uterus, ureter, and small and large intestines. The patient underwent open surgery 3 times and polypcctomies 6 times. Postoperative histopathologic analysis showed 2 adenomas and 8 carcinomas. Genetic analysis revealed microsatellite instabilities at the tested loci in all 10 tumors, indicating that replication errors played an essential role in the tumorigenesis. Early identification of microsatellite instability could be useful for predicting development of additional primary cancers.