Background: To better understand the malignant grade of gastric smooth muscle tumors, the DNA content of these tumors was studied.
Methods: In 43 patients with gastric smooth muscle tumors, the cellular DNA content was determined by flow cytometry and compared with the histologic classification and the prognosis.
Results: Flow cytometry indicated that all 21 leiomyomas and 9 of the 10 low-grade leiomyosarcomas were diploid; 10 of the 12 high-grade leiomyosarcomas were aneuploid. All patients with leiomyomas and 8 of the 11 patients with diploid leiomyosarcomas had neither local recurrence nor metastasis. By contrast, 8 of the 10 patients with aneuploid leiomyosarcomas died of their disease (mean survival, 41 months; range, 18-78 months).
Conclusions: These results indicate that the DNA ploidy pattern shown by flow cytometry is related closely to the histologic classification and prognosis of gastric smooth muscle tumors.