Microleiomyomas of human stomach.

The incidence and distribution of microleiomyomas occurring in human stomachs were investigated in a sample of 286 resected stomachs examined by a whole organ stepwise cutting method. Seventy-two micromyomatous lesions were found in 47 cases (16.4%), without any sexual predilection. Almost all lesions (94.4%) were less than 5 mm in diameter, the rest being in the range of 6 to 10 mm. Multiple lesions were found in 18 cases (38.3%). Histologically they were all benign leiomyomas. All 72 micromyomas were located in the upper half of the stomach; 22 (30.6%) were concentrated at the esophago-gastric junction. The predisposed site for micromyoma development exactly coincided with that area bearing an inner oblique muscle layer. The incidence of microleiomyoma was much lower, 2.2% (26/1,208), when specimens obtained by lower partial gastrectomy were studied for comparison. This indicated that variation in material investigated may be an important factor underlying the large discrepancies noted in previous reports concerning the incidence of microleiomyomas of the stomach.