- This was the first research thesis having the longest follow-up time (10 years) on all types of non-epithelial gastrointestinal malignancies consisting of all segments of the gastrointestinal tract from the esophagus to the anus, included: leiomyosarcoma, liposarcoma, shwannoma malignant, malignant lymphoma, gastrointestinal stroma tumor (GIST), angiosarcoma, glomus tumor, Kaposi tumor, granular tumor, rhabdomyosarcoma, malignant melanoma.