A case of rapidly growing gastric leiomyosarcoma: observations over 18 months.

A gastric leiomyosarcoma in a 68-yr-old female was followed for 18 months by serial roentgenography. On initial x-ray, the lesion was diagnosed as a benign submucosal tumor. However, it rapidly increased in size, with doubling time subsequently calculated as 5 months. After 18 months' periodic observation, a gastrectomy was performed for a suspected malignancy. Histologic examination of the resected tumor revealed a leiomyosarcoma originating in the muscular layer of the stomach. It appears that the poor prognosis of leiomyosarcoma is related to its rapid growth; in addition, it is seldom detected at an early stage. Follow-up of the patient with a gastric submucosal tumor should be done first, 6 months after the initial examination, and thereafter, be done continuously according to the patient's condition. It is useful in differentiating a benign from a malignant myogenic tumor.