The natural history of gastrointestinal subepithelial tumors arising from muscularis propria: an endoscopic ultrasound survey.

AIM

The majority of lesions originating from muscularis propria of stomach, duodenum, and colon are gastrointestinal stromal tumors (GISTs). Surgery is indicated when endosonographic criteria of malignancy are met, but little is known about the natural history of lesions with benign endosonographic features. Aim of this study was to evaluate the natural course of benign-appearing lesions originating from muscularis propria in organs where GISTs significantly overcome leiomyomas.

MATERIALS AND METHODS

A total of 49 asymptomatic patients with hypoechoic lesions originating from the fourth layer of the gastrointestinal tract entered a follow-up program by means of endoscopic ultrasonography. All lesions were nonulcerated, <3 cm in maximal diameter, with regular margins, and cystic spaces of <3 mm.

RESULTS

After a mean follow-up of 31+/-20.8 months and a median of 2 (range, 1 to 5) endosonographies/patient, no change in echostructure or dimensions was seen in 44 subjects whereas in 5, an increase of at least 25% in 1 diameter occurred. Surgical removal was proposed to all: 1 patient refused (she is still alive and symptom-free after 4 y), 3 of the 4 lesions removed proved to be GISTs with very low or low risk of malignancy and 1 lesion was classified as a glomus tumor with no malignant appearance.

CONCLUSIONS

Even small and benign-appearing lesions from muscularis propria may increase in size over time but this increase cannot be considered as an index of malignancy. As most of these lesions are GISTs, a policy of surveillance is advisable.