A Case of Primary Extragastrointestinal Stromal Tumor Presenting as Peritoneal Dissemination

Abstract

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract, but also occurs at a lower frequency in extra-gastrointestinal regions such as omentum, mesentery, retroperitoneum and undefined abdominal sites. This tumor is called extragastrointestinal stromal tumor (EGIST). EGIST is mostly diagnosed as a cystic mass, but rarely occurs as a disseminated abdominal tumor. We experienced a 70-year-old man with primary EGIST presenting as peritoneal dissemination. Abdominal CT showed diffuse peritoneal thickening with a large amount of ascites, but no definite mass lesion. Laparoscopic biopsy was performed and histologic findings showed tumor composed of epithelioid cells. In the results of immunohistochemical stains, the tumor showed positive reactivity with CD117 (c-kit), CD34, vimentin and actin, but negative reactivity with desmin and S-100 protein. On account of unresectability and histologic parameters of malignant behavior, he was started on imatinib.

Small Intestinal and Mesenteric Multiple Gastrointestinal Stromal Tumors Causing Occult Bleeding

“…Literature data suggest that tumors smaller than 10 cm are less likely to metastasize, have lower mitotic index and no intraperitoneal spread, and may be treated by R0 surgery [ 20 , 21 ]. Our case also had tumors less than 10 cm in size, which were excised according to the above criteria.…”

Postmenopausal recurrent retrovaginal extramural gastrointestinal stromal tumor: a case report

“…Such tumors are collectively called "extra-gastrointestinal stromal tumors (EGIST)", and account for 5-7% of incidence. They can occur in various parts of the abdominal cavity including the greater omentum, rectovaginal septum, peritoneum, retroperitoneum and vagina [3][4]. The early stage of vaginal wall GIST has no obvious symptoms, and most patients do not seek medical treatment until the tumor volume increases and compression symptoms appear, therefore the early detection rate is low.…”