EUS should be considered to distinguish a small GIST from extrinsic impression from normal or pathological adjacent structures as well as providing an accurate diameter which can be used to monitor the lesion. Esophageal GISTs appear hypoechoic on EUS and are seen to lie within the muscularis propria [2]. For this reason, endoscopic mucosal resection or endoscopic submucosal dissection are not diagnostic or therapeutic options. However, the authors could not identify any references to EUS appearances being able to reliably differentiate between GIST and leiomyoma or other mesenchymal tumor. EUS can, however, suggest higher malignant potential in some GIST tumors which display irregular extraluminal margins or cystic spaces [13].

Some authors suggest that EUS FNA may be used to differentiate esophageal GIST from leiomyoma [14, 15]. This is dependent on lesion size and on local endoscopic and pathology expertise and can often be inconclusive [3, 16]. The National Comprehensive Cancer Network guidelines do not suggest biopsy if a lesion is to be resected due to concern around tumor dissemination and bleeding, and if local resection of a potential leiomyoma is undertaken, mucosal injury is more likely [16]. This may not hold for larger lesions requiring extensive resection for which histological confirmation may be appropriate. Where EUS appearance suggests malignant behavior, EUS FNA or core biopsy may be indicated. For small submucosal tumors of the esophagus without EUS features of concern, therefore, EUS FNA is probably not indicated, and this is in accord with European guidelines [17].

Most small (<2 cm) GISTs elsewhere in the GI tract have negligible mitotic activity and have a very low malignant potential. There is some uncertainty in extrapolating this data for GISTs in the combined anatomical sites of esophagus, mesentery, omentum, colon or rectum which together make up only 10 % of all GISTs [18, 19]. Esophageal GISTs may have a higher malignant potential and further data on small esophageal GISTs is not likely to be forthcoming. For this reason, Rubinet al. [20] omits esophageal GIST from the table of likely malignant behavior for GISTs elsewhere.

Non-operative management mandates repeat assessment with EUS in 6 months with consideration given to further repeat imaging after another 12 months and potentially indefinitely. It seems reasonable to extend the period between observations if the lesion remains <2 cm and does not change in size.

Consensus opinion loosely supports the non-operative management of small asymptomatic GISTs, however this recommendation is not founded on an evidence base. Consensus opinion suggests that all symptomatic as well as asymptomatic GISTs >2 cm should be resected if possible. This recommendation is derived from guidelines for managing GISTs elsewhere in the GI tract; with a possible higher malignant potential, this advice would certainly seem appropriate for esophageal GISTs. Such a resection would ideally be radical, en bloc, with a 2 cm margin [19]. Rupture of the tumor must be avoided [21]. While GISTs do not tend to spread to lymph nodes, such spread has been reported and the few larger resected esophageal GISTs reported in the literature had a high recurrence rate despite R0 resection.