Clinicopathological study of gastric leiomyogenic tumors.

1. Seventy cases of the leiomyogenic tumors were found in 5451 resected stomachs; 49 leiomyoma, 17 leiomyosarcoma and 4 leiomyoblastoma. These leiomyogenic tumors occupied 40.5% of 173 submucosal tumors of the stomach. 2. The average age was 51.7 in leiomyoma, 57.3 in leiomyosarcoma and 41.6 in leiomyoblastoma with male predominance. 3. The leiomyoma and leimyosarcoma were frequently found in the upper 2/3 of the stomach. 4. The size of the tumors was within 3 cm in diameter in about 80% of leiomyoma with ulcer formation of 10.2% and over 3 cm in about 88% of leiomyosarcoma with ulcer formation of 64.7%. 5. The classification of the leiomyogenic tumors into the benign and malignant was occationally difficult. For the diagnosis of the leiomyosarcoma, the number of mitosis, irregularity of nucleus, increase of cellularity and decrease of smooth muscle production were helpful.