Imaging Pearls ❯ Stomach ❯ GIST Tumors
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- “Carney-Stratakis syndrome, first described in 2002, describes the dyad of familial paraganglioma and gastrointestinal stromal tumor. It is a unique entity, separate from the previously described Carney triad, which noted the association between paraganglioma, gastrointestinal stromal tumor (GIST), and pulmonary chondroma. Carney-Stratakis syndrome is associated with germline mutations in the succinate dehydrogenase genes SDHB, SDHC, and SDHD, with autosomal dominant inheritance and incomplete penetrance.”
Carney-Stratakis syndrome: A dyad of familial paraganglioma and gastrointestinal stromal tumor,
Hannah S. Recht, Elliot K. Fishman
Radiology Case Reports, Vol 15, Issue 11,2020, Pages 2071-2075, - “Carney-Stratakis syndrome is one of the familial GIST syndromes, which also includes primary familial GIST syndrome and neurofibromatosis type 1. However, while the familial GIST syndrome is associated with KIT and PDGFRA mutations, Carney-Stratakis syndrome is associated with germline mutations of the succinate dehydrogenase subunits B, C, and D.”
Carney-Stratakis syndrome: A dyad of familial paraganglioma and gastrointestinal stromal tumor,
Hannah S. Recht, Elliot K. Fishman
Radiology Case Reports, Vol 15, Issue 11,2020, Pages 2071-2075,
- “The stomach represents 16–22.7% of gastrointestinal tract locations of metastases from melanoma. Symptoms are often nonspecific including nausea, vomiting, abdominal pain, weight loss, and anemia. On imaging, gastric metastases generally present as intraluminal polypoid masses, although an infiltrative pattern has been described. They are hypoattenuating, with heterogeneous enhancement during the arterial phase and persisting enhancement during the portal phase.
CT, MRI and PET/CT features of abdominal manifestations of cutaneous melanoma: a review of current concepts in the era of tumor‐specific therapies
Maxime Barat et al.
Abdominal Radiology (2021) 46:2219–2235
- Gastric GIST Tumors: Treatment
Surgery is typically the initial therapy for the following types of patients:
- Those with primary GIST who do not have evidence of metastasis.
- Those with tumors that are technically resectable if the risks of morbidity are acceptable.
In the surgical treatment of GIST, the goal is complete gross resection with an intact pseudocapsule and negative microscopic margins. Because lymph node metastasis is rare with GIST, lymphadenectomy of clinically uninvolved nodes is not necessary. - GIST Tumor Resection
- Although a prospective, randomized trial studying the role of laparoscopic surgery in the management of GIST has not been performed, several studies, listed below, indicate a role for this surgical approach with gastric tumors:
- In one retrospective study involving 33 patients with gastric tumors ranging in size from 0.5 cm to 10.5.cm, all gross tumors could be successfully removed by laparoscopic surgery, with short hospitalizations and low morbidity. There were no recurrences observed with a mean follow-up of 13 months.[8][Level of evidence: 3iiDii]
- In another retrospective study involving 60 patients, laparoscopic or laparoscopy-assisted resections of GIST measuring 2 cm to 5 cm were associated with a 5-year DFS of 100% for very low-risk groups and low-risk groups versus a 5-year DFS of 89.9% for intermediate-risk groups and high-risk groups; no local or distant recurrences were observed for tumors smaller than 4 cm in size.[9][Level of evidence: 3iiDi] - Gastric GIST Tumor: Chemotherapy
Before the advent of molecularly targeted therapy with TKI, efforts to treat GIST with conventional cytotoxic chemotherapy were essentially futile The extreme resistance of GIST to chemotherapy may be caused, in part, by the increased expression of P-glycoprotein, the product of the MDR-1 gene, and MRP1, which are cellular efflux pumps that may prevent chemotherapeutic agents from reaching therapeutic intracellular concentrations in GIST cells. There is universal agreement that standard chemotherapy has no role in the primary therapy of GIST. - Gastric GIST Tumor: Tyrosine Kinase Inhibitor Therapy
- TKIs have revolutionized the management of GIST. The TKI imatinib mesylate is used as the first-line treatment for unresectable, metastatic, or recurrent GIST. Although complete responses are rare, a large majority of patients with metastatic or inoperable GIST have either a partial response or disease stabilization after starting imatinib. Median survival rates have gone from less than 2 years to more than 5 years since the advent of imatinib therapy.
- Therapy with neoadjuvant imatinib to reduce the tumor volume may be used for patients with very large primary GIST that cannot be removed without the risk of unacceptable morbidity. Additional therapy with adjuvant imatinib is being studied to determine whether imatinib reduces recurrence, which is common after resection of primary GIST. - Gastric GIST Tumors: Treatment
All GIST 2 cm or larger in size are typically resected; the management of incidentally encountered GIST smaller than 2 cm in size remains controversial. There is no evidence that patients should undergo re-excision in cases in which there is complete resection of all macroscopic disease but microscopically margins are positive; watchful waiting and adjuvant imatinib may be appropriate for these patients. In general, gastric GIST 5 cm or smaller in size may be removed by laparoscopic wedge resection. Because GIST rarely involve the locoregional lymph nodes, extensive lymph node resection or resection is rarely indicated. These tumors may have fragile pseudocapsules, so care must be taken to avoid rupturing the pseudocapsule during surgery, which could result in peritoneal dissemination. - Gastric GIST Tumors: Treatment
Therapy with postoperative adjuvant imatinib for GIST patients with completely resected localized disease is under investigation. This is a very heterogeneous population in terms of risk of relapse and death after surgical resection. Depending on mitotic count, tumor size, and tumor site, the risk of relapse after complete gross resection may be considerable. Results from two trials suggest that adjuvant imatinib reduces recurrence after complete resection of localized, primary GIST. However, it is not clear whether improvements in recurrence with adjuvant therapy will translate into improved survival. In addition, the optimal duration of adjuvant imatinib is unknown. - Gastric GIST Tumors: Treatment
Therapy with neoadjuvant imatinib is under evaluation. It may be used for patients with very large primary gastrointestinal stromal tumors (GIST) or poorly positioned small GIST (considered unresectable without the risk of unacceptable morbidity or functional deficit) until surgical therapy is feasible, which can take as long as 6 to 12 months. There are no controlled trials addressing the benefits of imatinib in this setting, so the impact of neoadjuvant imatinib on overall survival (OS) is unclear. Even the conversion rate from inoperability to operability with neoadjuvant therapy is ill-defined. Therefore, any advantages of neoadjuvant therapy are currently theoretical. - Gastric GIST Tumors: Treatment
- The primary treatment of patients with metastatic or recurrent gastrointestinal stromal tumors (GIST) involves medical therapy with a tyrosine kinase inhibitor (TKI); in select cases, surgical therapy may be added. Patients with metastatic or recurrent tumors that do not respond to these measures may be candidates for clinical trials.
- Therapy with imatinib is standard for patients with metastatic or recurrent disease. The initial dose may range from 400 mg to 600 mg daily, except for patients with tumors containing KIT exon 9 mutations, who may receive 800 mg daily. Response is evaluated with computed tomography (CT), magnetic resonance imaging (MRI), or fluorine F 18-fludeoxyglucose positron emission tomography (18F-FDG PET). Treatment is usually continued indefinitely in the absence of disease progression or unacceptable toxicity.] - Gastric GIST Treatment Info
https://www.cancer.gov/types/soft-tissue-sarcoma/hp/gist-treatment-pdq
- “All patterns of enhancement on contrast enhanced computed tomography (CECT) can be seen with GISTs, including hypoenhancing, isoenhancing, and hyperenhancing tumors. They can be large or small, endoluminal or exophytic. Clinical presentations include asymptomatic patients, nonspecific symptoms, obstruction, and bleeding. Bleeding can take the form of slow, intraluminal GI bleeding or massive intraperitoneal bleeding secondary to rupture and can be seen regardless of the enhancement pattern.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging.
Scola D et al.
Abdom Radiol 2017 May;42(5):1350-1364. - “The vast majority of GISTs are sporadic. Although rare, they can present in association with genetic syndromes including neurofibromatosis 1; Carney-Stratakis Syndrome, characterized by gastric GIST and paraganglioma; Carney Triad Syndrome which consists of (i) gastric GIST, (ii) pulmonary chondroma, and (iii) paraganglioma; and familial GIST syndrome.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging.
Scola D et al.
Abdom Radiol 2017 May;42(5):1350-1364. - “GISTs are the most common form of sarcoma, and as such no GIST can truly be classified as benign. Most patients have localized disease (79.4%), but approximately 11.4% have regional/distant metastatic disease at the time of presentation. Recurrences have been reported up to 30 years after initial diagnosis and resection. Metastasis during initial presentation or after resection more commonly involve the liver and peritoneal surfaces due to GISTs tendency for local invasion.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging.
Scola D et al.
Abdom Radiol 2017 May;42(5):1350-1364. - “Clinical presentations are highly variable and usually dependent on tumor size and location. Exophytic lesions are often large at the time of presentation, while smaller lesions that erode through the mucosa and result in mucosal ulceration can present earlier with GI bleeding. If visualized on endoscopy (stomach and duodenum) they can be mistaken for ulcers. If located in the distal small bowel, GISTs commonly present later as large cavitary masses. Often, patients are asymptomatic until the tumor reaches a large size. The most common symptoms are usually nonspecific, including abdominal pain, nausea, weight loss, or obstruction. Occasionally, patients may present with GI bleeding, which may be occult or take the form of frank hemorrhage with hemodynamic instability. Likewise, tumors can rupture on the external surface, causing intraperitoneal hemorrhage which can be life threatening.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging.
Scola D et al.
Abdom Radiol 2017 May;42(5):1350-1364. - “Clinical presentations are highly variable and usually dependent on tumor size and location. Exophytic lesions are often large at the time of presentation, while smaller lesions that erode through the mucosa and result in mucosal ulceration can present earlier with GI bleeding. The most common symptoms are usually nonspecific, including abdominal pain, nausea, weight loss, or obstruction. Occasionally, patients may present with GI bleeding, which may be occult or take the form of frank hemorrhage with hemodynamic instability. Likewise, tumors can rupture on the external surface, causing intraperitoneal hemorrhage which can be life threatening.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging.
Scola D et al.
Abdom Radiol 2017 May;42(5):1350-1364.
- “Mesenchymal tumors arise from mesenchymal cells in the gastric wall and include gastrointestinal stromal tumors (GISTs), non-GIST sarcomas, lipomas, lipomatosis, leiomyomas, schwannomas, and glomus tumors. GISTs are the most common subtype of mesenchymal tumors and can be either benign or aggressive. A well-circumscribed gastric mass with its epicenter in the submucosa and absence of perigastric lymphadenopathy favors a benign GIST diagnosis.”
Multimodality Imaging of Gastric Pathologic Conditions: A Primer for Radiologists
Anderson AC et al.
RadioGraphics 2020; 40:707–708 - Gastric GIST Tumor: Facts
- Most common gastrointestinal tract mesenchymal tumor (60%–70% occur in the stomach)
- Majority are benign; 10%–30% aggressive
- Arises from the interstitial cells of Cajal in the submucosa
- Immunoreactive to c-KIT and DOG-1 at immunohistologic examinations
--- Differentiates from other mesenchymal tumors, adenocarcinoma, and lymphoma
--- 5% may not show c-KIT reactivity
- Expresses a tyrosine kinase growth factor receptor that can be targeted for treatment - Gastric GIST Tumors: CT Findings
- Commonly found in the gastric body and antrum
- Benign
--- Well-circumscribed endophytic, exophytic, or bilobed mass with its epicenter in the submucosa
--- Ulceration can be visualized in lesions larger than 2 cm (bull’s eye sign)
- Aggressive
--- Large (>5 cm) heterogeneous mass
--- Necrosis, hemorrhage, with or without calcifications
--- Lymphadenopathy, with or without metastases
--- Invasion of adjacent viscera (pancreas, colon)
- Carney-Stratakis Syndrome
- Familial paraganglioma and GIST
--- Autosomal dominant
- Germline mutations in succinate dehydrogenase genes SDHB, SDHC or SDHD
--- No germline or somatic CKIT or PDGFRA mutations
- Mean age 23
--- Males and females affected
- Nearly all stomach
--- Frequently multiple and multinodular
- GIST may metastasize to lymph nodes
--- Usually protracted, indolent course (e.g. 15 years) in most cases even with metastasis or recurrence - Carney-Stratakis Syndrome
A diverse group of researchers has found the genetic defects that cause a rare type of familial GIST called “Carney-Stratakis syndrome”. This syndrome has some similarities to Carney’s Triad but it is a distinct entity. This discovery may one day lead to better treatments for the affected patients and may give researchers new insights into Carney’s Triad and possibly into pediatric GIST in general. - GIST Syndromes
- Primary familial GIST syndrome
- Neurofibromatosis type 1 (von Recklinghausen disease)
- Carney-Stratakis syndrome - Primary Familial GIST Syndrome
- This is a rare, inherited condition that leads to an increased risk of developing GISTs. People with this syndrome tend to develop GISTs at a younger age than when they usually occur. They are also more likely to have more than one GIST.
- Most often, this syndrome is caused by an abnormal KIT gene that is passed from parent to child. This is the same gene that is mutated (changed) in most sporadic GISTs. - Neurofibromatosis type 1 (von Recklinghausen disease)
- This condition is caused by a defect in the NF1 gene. This gene change may be inherited from a parent, but in some cases the change occurs before birth, without being inherited.
- People affected by this syndrome often have many benign (non-cancerous) nerve tumors, called neurofibromas, starting when they are young. These tumors form under the skin and in other parts of the body. These people also typically have tan or brown spots on the skin (called café au lait spots).
- People with NF1 have a higher risk of GISTs (most often in the small intestine), as well as some other types of cancer. - Carney-Stratakis Syndrome
- People with this rare inherited condition have an increased risk of GISTs (most often in the stomach), as well as nerve tumors called paragangliomas. GISTs often develop when these people are in their teens or 20s. They are also more likely to have more than one GIST.
- This syndrome is caused by a change in one of the SDH (succinate dehydrogenase) genes, which is passed from parent to child.
- "Though breast cancer is a common cancer it rarely metastasizes to stomach. Lobular carcinoma is the most common histological type which presents with gastric metastases. The most common presentation is linitis plastica."
Gastric metastases from breast cancer: A report of two cases and review of literature.
Rachan Shetty KS et al.
J Cancer Res Ther. 2015 Jul-Sep;11(3):660. - "Linitis plastica can affect the entire digestive system. Its potentially secondary nature necessitates a systematic search for a primary tumor. An appropriate CT protocol is required to detect the specific radiological features of this fibrous cancer. CT can help confirm the diagnosis of linitis plastica, rule out differential diagnoses, and indicate the need for deep biopsies where possible."
Computed tomography features of gastrointestinal linitis plastica: spectrum of findings in early and delayed phase imaging.
Burgain C et al.
Abdom Radiol (NY). 2016 Jul;41(7):1370-7. - "Gastric linitis plastica is a diffuse type of cancer which is characterized by a thickening and rigidity of the stomach wall. It is notorious for its failure to cause early symptoms, and patients with symptoms generally have a more advanced form of the disease."
Managing Gastric Linitis Plastica
Keep the scalpel sheathed
Sadaf Jafferbhoy et al
Qaboos Univ Med J. 2013 Aug; 13(3): 451–453. - "Linitis plastica denotes a diffuse type of carcinoma which accounts for 3–19% of gastric adenocarcinomas. It is characterized by a rigidity of a major portion, or all of the stomach, with the absence of a filling defect or extensive ulceration. Gastric carcinoma is notorious for its failure to cause early symptoms so that patients do not present themselves for diagnosis until late in the course of the disease. Because of the rich lymphatic supply, the cancer rapidly disseminates beyond the reach of surgical resection. Consequently, the patients with symptoms generally have far-advanced malignancy."
Managing Gastric Linitis Plastica
Keep the scalpel sheathed
Sadaf Jafferbhoy et al
Qaboos Univ Med J. 2013 Aug; 13(3): 451–453. - "Dyspepsia was the commonest feature of presentation (55%), followed by dysphagia (33%), vomiting (33%) and weight loss (33%). The infiltration of malignant cells reduces the volume of the stomach and interferes with peristalsis so that the stomach acts as a funnel between the oesophagus and duodenum. As a result, food is easily regurgitated into the oesophagus. This was the commonest presentation in these series."
Managing Gastric Linitis Plastica
Keep the scalpel sheathed
Sadaf Jafferbhoy et al
Qaboos Univ Med J. 2013 Aug; 13(3): 451–453. - "In conclusion, gastric linitis plastica is one of the forms of adenocarcinoma which usually presents at a later stage, where curative treatment is not an option for the majority of cases."
Managing Gastric Linitis Plastica
Keep the scalpel sheathed
Sadaf Jafferbhoy et al
Qaboos Univ Med J. 2013 Aug; 13(3): 451–453.
- "MDCT may be a reliable means of noninvasive diagnosis in the care of patients with endoscopically detected giant gastric folds and may be useful for differentiating benign from malignant disease."
MDCT of Giant Gastric Folds: Differential Diagnosis
Chen CY et al.
AJR 2010; 195:1124-1130
- “Non-cardial location, heterogeneous enhancement, presence of necrosis, larger lesion size, and absence of lymphadenopathy are highly suggestive CT findings for large GISTs in differentiation from schwannomas or leiomyomas. Regardless of radiologists' expertise, diagnostic performance in differentiation can be significantly improved with knowledge of these CT findings.”
Differentiation of large (≥ 5 cm) gastrointestinal stromal tumors from benign subepithelial tumors in the stomach: radiologists' performance using CT. Choi YR et al. Eur J Radiol. 2014 Feb;83(2):250-60
- “Heterogeneous enhancement, presence of necrosis, absence of lymph nodes, and mean size of ≥ 6 cm were found to be significant for differentiating GIST from schwannoma (P<0.05). Non-cardial location, heterogeneous enhancement, and presence of necrosis were differential CT features of GIST from leiomyoma (P<0.05). Multivariate analyses indicated that absence of enlarged LNs was the only statistically significant variable for GIST differentiating from schwannoma.”
Differentiation of large (≥ 5 cm) gastrointestinal stromal tumors from benign subepithelial tumors in the stomach: radiologists' performance using CT. Choi YR et al. Eur J Radiol. 2014 Feb;83(2):250-60
- “ Gastrointestinal stromal tumors (GISTs) account for the majority of intramural tumors and can vary in appearance, from small intraluminal lesions to exophytic masses that protrude into the peritoneal cavity, commonly with areas of hemorrhage or necrosis.”
Beyond the GIST: Mesenchymal Tumors of the Stomach
Kang HC et al.
RadioGraphics 2013; 33:1673-1690 - Intramural Gastric Tumors: Differential Dx
- Gastrointestinal stromal tumors (GIST)
- Non-GIST sarcomas
- Lipoma
- Leiomyoma
- Schwannoma
- Glomus tumors
- Hemangiomas
- Inflammatory fibrous polyps - Gastric GIST Tumors: Facts
- Represents 90% of mesenchymal tumors of the GI tract and 2-3% of all gastric malignancies
- Can arise anywhere in GI tract including mesentery, omentum and retroperitoneum
- Immunoreactivity for c-KIT (CD117) which is a growth factor receptor tyrosine kinase
- Treated with imatinib (Gleevec)- Gastric GIST Tumors: Facts
- Most commonly arises in the body of the stomach
- Malignant potential depends on mitotic rate, size and location
- Clinical presentation ranges from incidental finding to GI bleeding to abdominal pain and weight loss - Gastric GIST Tumors: CT Appearance
- Endoluminal location most common
- Focal ulceration common in larger tumors
- Calcification in tumor is not uncommon
- When large may invade adjacent structures including pancreas, colon or diaphragm
- Metastases at time of presentation are seen in half of the cases - Gastric GIST Tumors: Differential Dx
- Schwannoma
- Leiomyoma
- Solitary carcinoid tumors
- Lymphoma
- Metastases (melanoma, breast cancer)
- Gastric adenocarcinoma (rare) 
- Gastric Tumor Locations
- Cardia- leiomyoma
- Body- GISTs and schwannoma
- Antrum- glomus tumors, IFPs, lipomas, ectopic pancreas
- Gastric GIST tumors
- Previously referred to as gastric leiomyomas and leiomyosarcomas
- Stromal tumors are typically divided into myogenic tumors (arise from smooth muscle), neurogenic tumors (arise from neural elements) or less differentiated tumors.
- 1% of gastric tumors - GIST (Gastrointestinal Stromal Tumors): Facts
- Arise from common precursor cell
- Display spindle cell or epithelioid morphologic characteristics
- Immunohistochemical markers
- C-kit (CD117) protein (key for dx)
- CD34 protein
- S-100 and desmin (less common) - GIST (Gastrointestinal Stromal Tumors): Facts
- 60-70% of GIST tumors occur in the stomach
- 20-30% of GIST tumors arise in the small bowel
- They may also occur in the esophagus and colon - Gastric GIST Tumors
- 2.5% of all gastric tumors
- 10-30% are malignant
- Malignant risk increases with
- Extragastric location
- Size > 5cm
- Extension into adjacent organs
- > 1 mitosis per 50 high powered field - Gastric GIST Tumors: CT Findings
- Exogastric mass
- Ulcerations very common in malignant GIST’s
- Malignant GIST’s are often inhomogeneous with central necrosis
- Metastases to liver is most common site of metastases - Subepithelial Lesions of the Stomach: Differential Diagnosis
- Glomus tumor
- GIST
- Schwannoma
- Leiomyoma
- Leiomyosarcoma
- Neurofibroma
- Ganglioneuroma
- Paraganglioma
- Lipoma
- Granular cell tumor
- GIST Tumors: Facts Site of origin
- Stomach 60-70% of cases
- Small bowel 30% of cases
- Rectum, esophagus, colon and appendix are rare sites of tumor - Characterized as benign, borderline, low or high malignant potential based on the pathologic appearance.
- The vast majority express a mutant form of c-kit (CD117) that can be detected on routine staining.
- C-kit is a growth factor receptor with tyrosine kinase activity. It is thought that mutations in the c-kit gene are causative for the development of gastrointestinal tumors. It is found in both benign and malignant GIST. Treatment
- Surgical resection is the conventional therapy
- Prognosis of patients treated with surgery alone is discouraging. Rossi et al report that 10/18 pts developed recurrent disease after surgery
- Selective tyrosine kinase inhibitors, such as STI-571, have become the standard chemotherapy for metastatic or unresectable tumors. These agents are currently the focus of several clinical trials including RTOG and ACRIN- 10-30% are malignant
Malignant risk increases with- - Extragastric location
- Size > 5cm
- Extension into adjacent organs
- > 1 mitosis per 50 high powered field CT Findings
- intramural mass when small
- exophytic and bulky
- often central ulceration and /or necrosis
- do not usually produce significant adenopathy
- 3D CT is especially useful in determining organ of originPrognosis
- There is no general agreement on the prognosis of GIST.
- 5 year survival ranges from 28% - 43%. This broad range seen in different studies is likely explained by the inclusion of tumors mistaken to be GISTs.
- Improvement in survival with new treatments.- CT plays an important role for the diagnosis and staging of these neoplasms as CT can identify the tumor and assess for local spread or distant metastases.
- Characterized as benign, borderline, low or high malignant potential based on the pathologic appearance.The vast majority express a mutant form of c-kit (CD117) that can be detected on routine staining.
C-kit is a growth factor receptor with tyrosine kinase activity. It is thought that mutations in the c-kit gene are causative for the development of gastrointestinal tumors. It is found in both benign and malignant GIST.
- - Mesenchymal tumors
- Arise in association within the muscularis propria of GI tract wall
- Most frequent in the stomach (60%), but also can occur in the small bowel (30%), colon and rectum (5%), esophagus (<5%)
- 1-3 % of gastric malignancies - Gastrointestinal Stromal Tumors
- Mesenchymal tumors
- Arise in association within the muscularis propria of GI tract wall
- Most frequent in the stomach (60%), but also can occur in the small bowel (30%), colon and rectum (5%), esophagus (<5%)
- 1-3 % of gastric malignancies - Gastrointestinal Stromal Tumors
- Characterized as benign, borderline, low or high malignant potential based on the pathologic appearance.
- The vast majority express a mutant form of c-kit (CD117) that can be detected on routine staining.
- C-kit is a growth factor receptor with tyrosine kinase activity. It is thought that mutations in the c-kit gene are causative for the development of gastrointestinal tumors. It is found in both benign and malignant GIST. - Gastrointestinal Stromal Tumors
- CT Findings
- intramural mass when small
- exophytic and bulky
- often central ulceration and /or necrosis
- do not usually produce significant adenopathy
- 3D CT is especially useful in determine organ of origin - Gastrointestinal Stromal Tumors
- 10-30% are malignant
- Malignant risk increases with
- Extragastric location
- Size > 5cm
- Extension into adjacent organs
- > 1 mitosis per 50 high powered field - Gastrointestinal Stromal Tumors
- Treatment
- Surgical resection is the conventional therapy
- Prognosis of patients treated with surgery alone is discouraging. Rossi et al report that 10/18 pts developed recurrent disease after surgery
- Selective tyrosine kinase inhibitors, such as STI-571, have become the standard chemotherapy for metastatic or unresectable tumors. These agents are currently the focus of several clinical trials including RTOG and ACRIN. - Gastrointestinal Stromal Tumors
- Prognosis
- There is no general agreement on the prognosis of GIST.
- 5 year survival ranges from 28% - 43%. This broad range seen in different studies is likely explained by the inclusion of tumors mistaken to be GISTs.
- Improvement in survival with new treatments.