Two Cases of Smooth Muscle Tumor of the Stomach of Which Doubling Time Could be Measured from the Progress of Growth

Abstract

We report two cases of smooth muscle tumor of the stomach in which growth was monitored and doubling time could be measured from upper gastrointestinal X-ray finding. In case 1, a 56-year-old man, a tumor was detected on the cardia by an upper gastrointestinal series. Partial resection of the stomach was performed three years later. Histopathological examination revealed a smooth muscle tumor of underterminate malignant potential (STUMP) with a doubling time of 4.5 months. Incase 2, a 43-year-old woman, a tumor on the upper segment of the stomach was detected by an upper gastrointestinal series, and partial resection was performed about 20 months after the initial discovery. Histopathological examination revealed a STUMP with a doubling time of 25.4 months. The DNA patternwas diploid in both cases. It is often difficult to determine histopathologically whether smoothmuscle tumor is benign or malignant, but some reports have shown that the growth rate, that is, the doubling time of the tumor, is a useful index for determining its biological malignancy, We conclude that case 1 should be considered a leiomyosarcoma and case 2 a leiomyoma from the clinical aspect.