Imaging diagnosis
Case 204
【Progress】
He received open surgery to take out massive tumor arisen from small intestine that revealed gastrointestinal stromal tumor with dissemination to major omentum.
【Discussion】
Gastrointestinal soft tissue tumor arises from matrix of fibrin, smooth muscle, nerve, adipose tissue. Accurately, gene anomaly or mutation of creating soft tissue induces gastrointestinal soft tissue tumor. Gastrointestinal stromal tumor (GIST) arises in up to 20 persons per million people (1). Of all gastrointestinal soft tissue tumors, GIST emerges most with the incidence of 80%. Of all GISTs, the origin from stomach is most 60 - 70%, next small intestine 20 – 30%, and large intestine 5%, esophagus 5% (1). Of the soft tissue tumors, GIST is most in stomach and small intestine. Most of soft tissue tumors in small intestine are GIST. However, in esophagus, leiomyoma is most, 90% of the soft tissue tumors (1).
Histologic diagnosis for differentiating soft tissue tumor is conducted using immune-histologic-chemical stain with kit, desmin, S-100 protein (2-4). Positive kit with negative desmin and negative S-100 protein indicates GIST; positive desmin with negative kit and negative S-100 protein indicates leiomyoma: positive S-100 protein with negative kit and negative desmin indicates neurinoma. When kit is negative and CD34 positive, it indicates GIST.
GIST is thought to arise from interstitial cells of Cajal or its precursor cells since both of kit and CD34 are positive on Cajal cells alone but not on any other soft tissue cells. Kit gene makes kit (kinase of tyrosine) receptor on cell membrane as code. Stem cell factor coming from fibroblast or other stromal cells adheres (encodes) to kit receptor which induces activation of cell growth and cell differentiation. Stem cell factor is called ligands, a kind of cytokine. Stem cell factor (ligands) control the cell growth and cell differentiation. CD34 indicates also stem cell surface antigen which functions to create new vessels, following stimulation by encoding of ligands (2-4). Actually GIST owns hyper-vascular tumor vessels. When mutation of kit gene, CD34 gene or platelet-derived growth factor receptor (PDGFRA) occurs, cell growth, cell differentiation and/or new vessel formation initiates and automatically proliferates without control of ligands, inducing formation of GIST (5).
Imanitib called Glypeck which is tyrosine-kinase inhibitor, is used for advanced GIST or recurrent GIST (6). In our case, abdomen contrast-enhanced CT showed giant GIST with massive necrosis and gas formation arisen from small intestine and multiple liver metastases. Surgical tumor resection was first conducted. During open surgery, liver metastases and multiple dissemination of the tumor to greater omentum were confirmed. He was scheduled to be given Imanitib.
Greater omentum arise and descend from grater curvature of stomach and ascend and fuses to mesocolon of transverse colon. It connects to hepato-duodenal ligament at right lateral side and spleen-gastric ligament at left lateral side. Ovarian cancer, stomach cancer and other peritoneal tumors can disseminate to greater omentum which plays a role of defense against inflammatory and tumor attack. The reality of defense is a milky spot composed of macrophages and lymphocytes (7-9). CT showed the greater omentum anteriorly in the greater peritoneal space. Omental cake indicates tumor infiltration with nodules to the greater omentum.
【Summary】
We present a sixty one-year-old male with gastrointestinal stromal tumor (GIST) arisen from small intestine. Contrast-enhanced abdomen CT showed giant tumor with necrosis and gas formation, and omental dissemination plus multiple liver metastases. He received open surgery for palliative tumor resection. Thereafter, he was scheduled to be given Imatinib. It is borne in mind that kit and CD34 are positive for GIST, desmin is positive for leiomyoma and S-100 protein for neurinoma. GIST comes out from interstitial cells of Cajal. Kit gene makes kit (kinase of tyrosine) receptor on cell membrane as code. Stem cell factor as encode which is called legands (a kind of cytokine) producing from stromal cells adheres to the receptor. It activates cell growth and differentiation in a healthy condition. When kit gene mutation occurs, cell proliferation and cell differentiation occur automatically without control, inducing to become GIST. Similarly, platelet-derived growth factor receptor α (PDGFRA) is made by PDGFRA gene. PDGFRA mutation is also thought to induce to make GIST. Imanitib which is a repressive agent of tyrosine kinase is a medicine used for GIST.
【References】
1.Parab, TM, et al. Gastrointestinal stromal tumors: a comprehensive review. J Gastrointest Oncol. 2019; 10: 144–154.
2.Thomsen L. et al. Interstitial cells of Cajal generate a rhythmic pacemaker current. Nat Med. 1998; 4: 848-851
3.Isozaki K, et al. Disturbed intestinal movement, bile reflux to the stomach, and deficiency of c-kit-expressing cells in Ws/Ws mutant rats. Gastroenterology. 1995;109:456-464.
4.Hirota S, et al. Gain-of-Function Mutations of c-kit in Human Gastrointestinal Stromal Tumors. Science 1998; 279, Issue 5350: 577-580
5.Hirota S, et al. Gain-of-function mutations of platelet-derived growth factor receptor α gene in gastrointestinal stromal tumors. Gastroenterology. 125; 660-667, 2003
6.DeMatteo RP, et al. Placebo-Controlled Randomized Trial of Adjuvant Imatinib Mesylate Following the Resection of Localized, Primary Gastrointestinal Stromal Tumor (GIST). Lancet 2009; 373(9669): 1097-1104
7.Sompayrac SW,et al. The greater omentum. AJR Am J Roentgenol. 1997;168:683–687.
8.Krist LFG, et al. Milky spots in the greater omentum are predominant sites of local tumour cell proliferation and accumulation in the peritoneal cavity. Cancer Immunol Immunother. 1998;47:205–212.
9.Platell C, et al. The omentum. World J Gastroenterol. 2000;6:169–176.
2020.9.9