Imaging Pearls ❯ Small Bowel ❯ GIST Tumors
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- “Gastrointestinal stromal tumours (GISTs) are defined as CD117-positive primary, spindled or epithelioid, mesenchymal tumours of the gastrointestinal tract, omentum, or mesentery. While computed tomography (CT) is the recommended imaging modality for GISTs, overlap in imaging features between GISTs and other gastrointestinal tumours often make radiological diagnosis and subsequent selection of the optimal therapeutic approach challenging. Cinematic rendering is a novel CT post-processing technique that generates highly photorealistic anatomic images based on a unique lighting model. The global lighting model produces high degrees of surface detail and shadowing effects that generate depth in the final three-dimensional display. Early studies have shown that cinematic rendering produces high-quality images with enhanced detail by comparison with other three-dimensional visualization techniques. Cinematic rendering shows promise in improving the visualization of enhancement patterns and internal architecture of abdominal lesions, local tumour extension, and global disase burden, which may be helpful for lesion characterization and pretreatment planning.”
Stromal Tumours: A Review of Current Possibilities and Future Developments
Maxime Barat, Anna Pellat, Benoit Terris, Anthony Dohan, Romain Coriat, Elliot K. Fishman , Steven P. Rowe, Linda Chu, and Philippe Soyer
Canadian Association of Radiologists Journal2024, Vol. 75(2) 359–368 - “Cinematic rendering (CR) is a relatively recent technique for visualization of volumetric data that provides photorealistic 3D views from CT data owing to the use of more physical photon effects by comparison with traditional 3D representations. In that regard, the very realistic representation of complex lighting interactions gives more surface detail and enhances the evaluation of spatial relationships by comparison with volume-rendered images. The 3D views provided byCR are advantageous for preoperative planning of a variety of tumours compared to more traditional 3D imaging. To date, CR has been applied to a variety of abdominal conditions including, but not exhaustively, pancreatic, gastric, colonic, hepatic, and splenic diseases. However, the application of CR to GISTs has received little attention to date.”
Stromal Tumours: A Review of Current Possibilities and Future Developments
Maxime Barat, Anna Pellat, Benoit Terris, Anthony Dohan, Romain Coriat, Elliot K. Fishman , Steven P. Rowe, Linda Chu, and Philippe Soyer
Canadian Association of Radiologists Journal2024, Vol. 75(2) 359–368 - “CR visualizations in the workup of GISTs can accentuate the dynamic enhancement pattern through more distinctly highlighting the anatomy of the enhancing portions within the lesion. CR confers the added benefit of dynamic window width and level adjustment, which can aid in delineating cystic or necrotic areas within the tumour . CR helps demonstrate the extraluminal growth and the relationship of GIST to underlying mucosa, overlying serosa, and vessels, which has the potential to further surgical or endoscopic treatment planning. CR is also valuable in detecting or excluding small bowel bleeding from the tumour.”
Stromal Tumours: A Review of Current Possibilities and Future Developments
Maxime Barat, Anna Pellat, Benoit Terris, Anthony Dohan, Romain Coriat, Elliot K. Fishman , Steven P. Rowe, Linda Chu, and Philippe Soyer
Canadian Association of Radiologists Journal2024, Vol. 75(2) 359–368 - “CR offers the potential for comprehensive assessment of GISTs. CR can potentially improve the appreciation of the spatial relationship between the GIST and surrounding organs and delineation of the major vascular supply, which may influence endoscopic or surgical planning. However, this is done at a penalty of additional post-processing. In the future, CR implementation would require a more standardized and user-friendly interface, with the ultimate goal of being entirely automated with the help of artificial intelligence algorithms.”
Stromal Tumours: A Review of Current Possibilities and Future Developments
Maxime Barat, Anna Pellat, Benoit Terris, Anthony Dohan, Romain Coriat, Elliot K. Fishman , Steven P. Rowe, Linda Chu, and Philippe Soyer
Canadian Association of Radiologists Journal2024, Vol. 75(2) 359–368 - “The applications of CR as a post-processing tool in the evaluation of GISTs are growing. CR enhances the subtle texture changes between GIST and adjacent normal gastrointestinal mucosa that may improve tumour detection. The pseudoendoluminal views created from CR simulate an actual endoscopic view that can assist in resection. CR effectively displays the relationship between GIST and the surrounding structures, and can assist in operative planning. Considering the improved image detail of CR and favorable observer perceptions, the technique is gaining wide acceptance in many institutions. The next step should be to investigate how CR can be implemented in the real-life setting and how it can positively influence patient care and outcome. Future studies including large numbers of patients and based on randomized assignment of radiologists and physicians to have and not have access to CR images to estimate the net benefit of CR in terms of diagnostic confidence and patient outcome. Finally, incorporation of CR images in artificial intelligence pipelines should be a future challenge for GIST imaging.”
Stromal Tumours: A Review of Current Possibilities and Future Developments
Maxime Barat, Anna Pellat, Benoit Terris, Anthony Dohan, Romain Coriat, Elliot K. Fishman , Steven P. Rowe, Linda Chu, and Philippe Soyer
Canadian Association of Radiologists Journal2024, Vol. 75(2) 359–368
- NF1 and GIST Tumors
Neurofibromatosis type 1 (NF1) is characterized by café-au-lait patches on the skin and the presence of neurofibromas. Gastrointestinal stromal tumor (GIST) is the most common non-neurological tumor in NF1 patients. In NF1-associated GIST, KIT and PDGFRA mutations are frequently absent and imatinib is ineffective. - “Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors that can occur anywhere in the gastrointestinal tract and fall into low-risk, low-to-intermediate–risk, and high-risk categories. They generally manifest at a median patient age of 60 years but may manifest earlier in tumor syndromes such as Carney triad, Carney-Stratakis syndrome, and neurofibromatosis type 1 (NF1). Approximately 1.5% of all GISTs diagnosed are in patients with NF1. The prevalence of GISTs in patients with NF1 is unknown, due to the fact that many GISTs are small and asymp-tomatic, but has been reported as 7%.”
Gastrointestinal Stromal Tumors and their Appearance in Patients with Neurofibromatosis Type 1.
Murphy AN, Kearns C.
Radiographics. 2022 Jul-Aug;42(4):E111-E112. - “GISTs originate from precursors of the in-terstitial cells of Cajal, pacemaker cells that are responsible for peristalsis. In sporadic cases, immunohistochemistry results are positive for CD117 (KIT), a tyrosine kinase growth factor receptor, and/or DOG1. For GISTs that develop in patients with NF1, the pathogenesis s believed to be different from that of sporadic GISTs, and the typical KIT mutation is absent. Therefore, imatinib therapy is not typically used in these cases. Most GISTs in patients with NF1 show low mitotic activity and display relatively benign behavior.”
Gastrointestinal Stromal Tumors and their Appearance in Patients with Neurofibromatosis Type 1.
Murphy AN, Kearns C.
Radiographics. 2022 Jul-Aug;42(4):E111-E112. - GISTs vary in appearance and can display an exophytic, endophytic, or dumbbell-shaped growth pattern. Larger GISTs can undergo cystic degeneration, ulceration, necrosis, or hemorrhage or can result in fistulas. Calcifications are rare, and lymphadenopathy is not an associated feature. The differential diagnosis at imaging includes schwannomas, leiomyomas, and solitary carcinoid tumors. In patients withNF1, GISTs are classically multiple, small, and located in the small bowel.”
Gastrointestinal Stromal Tumors and their Appearance in Patients with Neurofibromatosis Type 1.
Murphy AN, Kearns C.
Radiographics. 2022 Jul-Aug;42(4):E111-E112.
- “Despite sharing many of the same histologic features, NF1-associated GISTs differ from most other GISTs in that they usually test negative for KIT or PDGFRA mutations. Rather, the mutation in NF1 unleashes a similar cascade of events largely through the overactivation of RAS in the setting of a dysfunctional neurofibromin protein. RAS-MAP kinase pathway appears be particularly important in this class of GISTs and may have a role in the diffuse ICC hyperplasia found in many of these patients. Additionally, the hyperplastic cells may represent precursor lesions that could account for the different clinical presentation of these GISTs. While NF1-associated GISTs tend to have a rash of negative prognostic signs including small intestinal involvement, multiple foci, and younger age of onset, they in fact have a more indolent course.”
Neurofibromatosis-associated Gastrointestinal Stromal Tumor Causing Small Bowel Obstruction.
Schaeffer HD, Griffiths RL, Factor MS.
The American Surgeon. 2022;88(7):1541-1542. - "Multiple gastrointestinal stromal tumors (GISTs) of the small intestine is an uncommon finding but can be a marker for underlying neurofibromatosis type 1 (NF1). We present the case of the 38-year-old male without prior NF1 diagnosis who presented with a small bowel obstruction. His physical exam was notable for cutaneous nodules and café-au-lait spots. He progressed to peritonitis and underwent an exploratory laparotomy, which revealed a 6-cm hemorrhagic mass along the antimesenteric border of the jejunum, causing obstruction and perforation. Pathology was consistent with GISTs. NF1-associated GISTs differ from wild-type GISTs in that they are unlikely to have C-KIT and PDGFRA mutations and therefore do not respond to imatinib. Treatment is largely limited to surgical resection; however, there is evidence that MEK inhibitors may prove an additional treatment strategy.”
Neurofibromatosis-associated Gastrointestinal Stromal Tumor Causing Small Bowel Obstruction.
Schaeffer HD, Griffiths RL, Factor MS.
The American Surgeon. 2022;88(7):1541-1542. - “Neuroendocrine neoplasms (NENs) are a group of neoplasms arising from the diffuse endocrine system (DES). The gastrointestinal tract (GIT) is the most common site of NEN. The WHO classification divides NEN into three broad categories viz. well-differentiated NENs, poorly differentiated NENs, and mixed neuroendocrine-non-neuroendocrine neoplasms. All GIT NEN have the potential to synthesize and secrete various bioactive substances which may lead to various clinical syndromes. The NEN may occur anywhere in the GIT and exhibit varying clinical presentation, prognosis, and metastatic potential. Further, some tumors show association with familial syndromes like multiple endocrine neoplasia type 1 and neurofibromatosis type 1.”
Radiology of the neuroendocrine neoplasms of the gastrointestinal tract: a comprehensive review.
Malla S, Kumar P, Madhusudhan KS.
Abdom Radiol (NY). 2021 Mar;46(3):919-935.
- "Approximately 40% of GISTs arise in the small bowel, most often in the duodenum or jejunum. GISTs are unique mesenchymal tumors that arise from the interstitial cells of Cajal. They are defined by their expression of KIT (CD117), a tyrosine kinase growth factor receptor. Immu- noreactivity for KIT distinguishes GISTs from other mesenchymal tumors such as leiomyoma, neurofibroma, and schwannoma and determines the appropriateness of KIT inhibitor therapy.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038 - "Benign GISTs are much more common than malignant GISTs and may be indistinguishable from other mesenchymal tumors at imaging. At CT and MRI, benign GISTs are seen as well-circumscribed variably enhancing soft-tissue masses that often show poor enhancement. GISTs often extend exophytically from the bowel lumen and may contain calcification.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038 - "Some estimation of tumor activity may be inferred from lesion size and degree of contrast material uptake. Imaging also helps identify areas of necrosis and hemorrhage. Malignant tumors are larger than benign lesions andtend to have larger areas of necrosis as well as greater enhancement. Tumor diameter greater than 10 cm is a strong predictor of malignancy. Local invasion is an unequivocal indicator of malignancy. GISTs are considered to have malignant potential irrespective of their imaging features, and surgical resection is warranted irrespective of their size.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038 - “Malignant GIST tends to appear as a large, bulky, predominantly exophytic mass. At CT and MRI, it can be seen as a heterogeneous, enhancing, lobulated mass with areas of hypo- or hyperenhancement, necrosis, ulceration, cavitation, or hemorrhage. There may be associated metastases to the liver, omen- tum, or peritoneum. However, bulky lymphadenopathy is uncommon and would favor other neoplasms, including lymphoma or metastatic disease.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038 - "Carcinoid tumor arises from the chromaffin cells at the base of the crypts of Lieberkühn. It most frequently arises in the distal ileum, Meckel diverticulum, or appendix and can be multifocal. Carcinoid tumor represents 25% of primary tumors of the small bowel, and 90% of small bowel carcinoid tumors arise in the distal ileum. Detection of primary carcinoid tumor in the small bowel is difficult with conventional imaging owing to the small size of the primary tumor (often less than a centimeter) and its location in the submucosa. More often, a spiculated mesenteric mass from metastatic disease is detected with imaging.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038 - “The endoexoenteric (cavitary) form appears as a large soft-tissue mass that communicates with the bowel lumen and appears cavitary. It represents a sealed-off localized perforation of bowel into the soft-tissue mass in the mesenteric space. Contrast material or gas can be seen in the soft-tissue mass, and this should not be mistaken for an abscess. Associated lymphadenopathy may help distinguish this form of intestinal lymphoma from a malignant GIST.”
Small Bowel Neoplasms: A Pictorial Review
Jasti R, Carucci LR
RadioGraphics 2020;40:1020-1038
- “Although the small intestine accounts for over 90% of the surface area of the alimentary tract, tumors of the small intestine represent less than 5% of all gastrointestinal tract neoplasms. Common small bowel tumors typically are well evaluated with cross-sectional imaging modalities such as CT and MR, but accurate identification and differentiation can be challenging. Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique.”
Multimodality imaging of small bowel neoplasms.
Williams EA1, Bowman AW2
Abdom Radiol (NY). 2019 (in press) - “Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique. While endoscopic evaluation is typically more sensitive for the detection of intraluminal tumors that can be reached, CT and MR, as well as select nuclear medicine studies, remain superior for evaluating extraluminal neoplasms. Understanding the imaging characteristics of typical benign and malignant small bowel tumors is critical, because of overlapping features and associated secondary complications.”
Multimodality imaging of small bowel neoplasms.
Williams EA, Bowman AW
Abdom Radiol (NY). 2019 (in press) - Small Bowel GIST Tumors
- Most common primary mesenchymal tumor of GI tract
- Usually seen in patients > 40 years of age
- Variable in size and appearance, often well-circumscribed
- May calcify, often exophytic
- Enhancement may be homogeneous or heterogeneous - “GIST is the most common mesenchymal neoplasm of the gastrointestinal tract, including both benign and malignant varieties, and they are most commonly seen in patients over 40 years of age. They occur throughout the small bowel, classically as a well-marginated mass of variable size. Though they begin as mural masses, they can protrude into the lumen or grow exophytically. When presenting as an extraserosal mass, identifying the origin can be challenging.”
Multimodality imaging of small bowel neoplasms.
Williams EA, Bowman AW
Abdom Radiol (NY). 2019 (in press) - Small Bowel GIST: Pearls
- Tumors can be very large and markedly exophytic, with a heterogeneous appearance on CT and MR because of hemorrhage and necrosis.
- Calcification sometimes occurs, similar to leiomyoma
- These tumors are often hypervascular following IV contrast administration and can be hypermetabolic on PET imaging - ”Malignant GISTs can present with metastases to the liver, omentum, and peritoneum. Lymphatic spread and retraction of the mesentery are unusual features compared to other malignancies affecting the small bowel. Recurrent disease following surgical resection is not uncommon in the setting of malignant GIST”.
Multimodality imaging of small bowel neoplasms.
Williams EA, Bowman AW
Abdom Radiol (NY). 2019 (in press) - ” Malignant GISTs can present with metastases to the liver, omentum, and peritoneum. Lymphatic spread and retraction of the mesentery are unusual features compared to other malignancies affecting the small bowel. Recurrent disease following surgical resection is not uncommon in the setting of malignant GIST ”.
Multimodality imaging of small bowel neoplasms.
Williams EA, Bowman AW
Abdom Radiol (NY). 2019 (in press) - “This case series reveals an important significant association between heterogeneous enhancement and non-low risk (ie, moderate/high) SB-GISTs. Beyond just describing the tumor, using enhancing pattern, the interpreting radiologist can preoperatively suggest additional prognostic information, potentially helpful for surgical planning.”
Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression
Verde F, Hruban RH, Fishman EK
Comput Assist Tomogr. 2017 May/Jun;41(3):407-411. - “Small bowel cancers are very rare despite the length and large mucosal surface of the small bowel and account for 3% to 6% of all gastroin- testinal (GI) tract malignancies. Adenocarcinoma, neuroendocrine neoplasms, lymphoma, and GI stromal tumors (GISTs) are the most prevalent primary small bowel cancers, with adenocarcinoma and neuroendocrine neoplasms accounting for nearly two-thirds of small bowel cancers.”
Imaging and Screening of Cancer of the Small Bowel
Jin Sil Kim et al.
Radiol Clin N Am (2017) (in press) - “A variety of conditions increase the risk of small bowel GISTs. Familial GIST is autosomal dominant and often leads to the development of a single or multiple GISTs in middle age. Additionally, about 5% of patients with neurofibromatosis type 1 (NF-1) will present with a small bowel GIST; GISTs can be seen in young females as part of the Carney triad (gastric or small bowel GIST, pulmonary chondroma, and extra-adrenal pheochromocytoma) or in males or females as part of the Carney-Stratakis syndrome (GIST and paraganglioma).”
Imaging and Screening of Cancer of the Small Bowel
Jin Sil Kim et al.
Radiol Clin N Am (2017) (in press) - Small Bowel GIST Tumors: Facts
- Most common mesenchymal tumor of the gastrointestinal tract.
- Increased incidence in NF-1 patients
- Most common in the stomach followed by small bowel
- May present as GI bleed when the lesions are smaller and the tumor very vascular
- Larger tumors are usually of higher grade than smaller tumors - GIST Tumors of the Small Bowel: Clinical Presentation
- bowel obstruction
- intraluminal GI bleeding (occult or frank) from mucosal ulceration
- intraperitoneal bleeding secondary to rupture - Small Bowel Tumors: CT Attenuation
- “They are typically well-circumscribed tumors and usually arise from the muscularis propria of the gastrointestinal tract. The classic tendency is for exophytic growth, especially since they arise from the outer muscular layer. There is usually some growth towards the lumen however, as up to 50% of GISTs will exhibit mucosal ulceration on the luminal surface.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “The size of tumors is highly variable, ranging from several millimeters to greater than 30 cm; the median tumor size for those considered high-risk (e.g., locally advanced primary tumor or metastatic/recurrent tumor) is reported as 8.9 cm .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “Up to 30% of GISTs have poor prognostic factors including size >5 cm, lobulated contour, heterogeneous enhancement, presence of mesenteric fat infiltration, ulceration, regional lymphadenopathy or an exophytic growth pattern on CT .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “They most commonly arise in the stomach (approximately 60%), followed by the jejunum/ileum (30%), duodenum (5%), colon (4%), and esophagus or appendix (1%). Even more rare are primary extra-intestinal locations. Clinical presentations are highly variable and usually dependent on tumor size and location .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “GISTs occurring in the duodenum and remainder of the small bowel can also demonstrate any growth pattern but are commonly exophytic, possibly explained by slow growth and often delayed presentations. Calcifications are uncommon but can occasionally be present within larger GISTs. When large, enhancement is often heterogeneous, and there can be large hypo-attenuating necrotic components. They can also be arterially hyper-enhancing.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “If a tumor is larger than 5 cm, and if removal would result in excessive damage to surrounding structures, it is typically considered unresectable. In these instances, treatment with targeted therapy (such as imatinib mesylate) is performed. Because mutational activation of TK receptors (KIT or PDGFRA) stimulates growth, targeted therapy agents are tyrosine kinase inhibitors, selectively blocking the GIST’s growth signal. Targeted therapy after surgical resection has become the standard of care to help prevent recurrence or treat recurrence or metastatic disease.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “Imaging evaluation of GISTs tumors using rapid reduction in size to indicate treatment response to target therapies can be used as in the Response Evaluation Criteria in Solid Tumors (RECIST) criteria . In these instances rapid decrease in tumor size and number of lesions has been described. However size criteria alone underestimates/misinterprets good response, as stable or initially increasing size has been described . FDG PET can increase accuracy of RECIST criteria by showing decreasing FDG-avidity over time.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
Scola D, Bahoura L, Copelan A. et al.
Abdom Radiol (2017) 42: 1350-1364 - “The most frequent clinical indication for imaging, which led to detection of the small bowel GISTs in our series, was suspected small bowel bleeding (45/111; 40.5%), with 34/45 of these patients having (75.5%) overt and 11/45 (24.5%) having occult small bowel bleeding. Abdominal pain was the indication for imaging in slightly over one-third of patients (41/111; 37%), with cancer surveillance in asymptomatic patients accounting for 9% (10/111) and clinical suspicion for potential small bowel tumor in 13% (15/111).”
Impact of CT enterography on the diagnosis of small bowel gastrointestinal stromal tumors
Vasconcelos, R.N., Dolan, S.G., Barlow, J.M. et al.
Abdom Radiol May 2017, Volume 42, Issue 5, pp 1365–1373 - “The association of gastrointestinal stromal tumors with NF1 has been recently recognized in the medical literature. In all reports to date, the gastrointestinal stromal tumors occurring in patients with NF1 are located in the small intes- tine and are multiple or occur in association with other intestinal neoplasms. Abdominal pain and bleeding are the most common presenting symptoms.”
Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
Angela D. Levy et al.
RadioGraphics 2005; 25:455– 480 - “Gastrointestinal stromal tumors associated with NF1 are histologically and immunophenotypically identical to those that occur in patients without NF1. The distinguishing features of gastrointestinal stromal tumors in NF1 are their predominant location in the small intestine and their tendency for multiplicity. Gastrointestinal stromal tumors arise in or near the muscularis propria of the gastrointestinal tract wall and may have intramural, intraluminal, or extraluminal growth.”
Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
Angela D. Levy et al.
RadioGraphics 2005; 25:455– 480 - The biologic behavior of gastrointestinal stromal tumors in patients with NF1 does not appear to be different than that of such tumors in patients without NF1. The tumors may be benign, be malignant, or have uncertain malignant potential based on the current understanding of gastrointestinal stromal tumors.”
Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
Angela D. Levy et al.
RadioGraphics 2005; 25:455– 480 - “On CT and MR images, the tumors are heterogeneously enhancing masses with focal areas of cystic change or evidence of hemorrhage. The tumors have an intramural location and may extend intraluminally, simulating a polypoid mass, or exophytically into the adjacent mes- entery.”
Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
Angela D. Levy et al.
RadioGraphics 2005; 25:455– 480
- “Small bowel gastrointestinal stromal tumors (SB-GISTs) account for 8% to 15% of all primary small bowel neoplasms. They are thought to arise from a precursor of interstitial cells of Cajal found through the gastrointestinal tract. They involve the duodenum, jejunum, and ileum in order of decreasing frequency. Small SB-GISTs can be found incidentally or part of a surgical specimen to resect another tumor (eg, duodenal GIST found in a Whipple specimen). Larger tumors can present with obstruction, pain, or GI bleeding.”
Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression Franco Verde, Ralph H. Hruban, Elliot K. Fishman J Comput Assist Tomogr 2017;41: 407–411 - “This study demonstrated interesting significant associations between heterogeneous enhancement pattern and presence of necrosis and also histologic risk of tumor progression. The difference in enhancement reflects the underlying pathologic change which is thought to be necrosis. As tumors enlarge, they outstrip their blood supply and become necrotic which is suggested by the significant association between heterogeneous enhancement, necrosis, and increasing size.”
Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression Franco Verde, Ralph H. Hruban, Elliot K. Fishman J Comput Assist Tomogr 2017;41: 407–411 - “Heterogeneous enhancement was significantly associated with non-low (ie, moderate or high) risk of tumor progression. This association was expected as heterogeneity reflects necrosis which is associated with increasing size. Size is a determinant in risk of progression hence the assumption can be made that
heterogeneous enhancement indirectly reflects risk.”
Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression Franco Verde, Ralph H. Hruban, Elliot K. Fishman J Comput Assist Tomogr 2017;41: 407–411 - “Heterogeneous
enhancement was significantly associated with the presence of necrosis, larger size, and non-low (ie, moderate or high) risk of tumor progression. Radiologists can preoperatively offer prognostic information which may help surgical planning.”
Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression Franco Verde, Ralph H. Hruban, Elliot K. Fishman J Comput Assist Tomogr 2017;41: 407–411
- “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. 
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- GIST Tumors: Site of Origin
• stomach (approximately 60%)
• jejunum/ileum (30%)
• duodenum (5%)
• colon (4%)
• esophagus or appendix (1%) - “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 My;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 My;42(5):1350-1364.
- Small Bowel GIST Tumors: Facts
• Most common mesenchymal tumor of the gastrointestinal tract.
• Increased incidence in NF-1 patients
• Most common in the stomach followed by small bowel
• May present as GI bleed when the lesions are smaller and the tumor very vascular
• Larger tumors are usually of higher grade than smaller tumors - GIST Tumors of the Small Bowel:
Clinical Presentation
• bowel obstruction
• intraluminal GI bleeding (occult or frank) from mucosal ulceration
• intraperitoneal bleeding secondary to rupture - Small Bowel Tumors:CT Attenuation
- “They are typically well-circumscribed tumors and usually arise from the muscularis propria of the gastrointestinal tract. The classic tendency is for exophytic growth, especially since they arise from the outer muscular layer. There is usually some growth towards the lumen however, as up to 50% of GISTs will exhibit mucosal ulceration on the luminal surface.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “The size of tumors is highly variable, ranging from several millimeters to greater than 30 cm; the median tumor size for those considered high-risk (e.g., locally advanced primary tumor or metastatic/recurrent tumor) is reported as 8.9 cm .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “Up to 30% of GISTs have poor prognostic factors including size >5 cm, lobulated contour, heterogeneous enhancement, presence of mesenteric fat infiltration, ulceration, regional lymphadenopathy or an exophytic growth pattern on CT .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “They most commonly arise in the stomach (approximately 60%), followed by the jejunum/ileum (30%), duodenum (5%), colon (4%), and esophagus or appendix (1%). Even more rare are primary extra-intestinal locations. Clinical presentations are highly variable and usually dependent on tumor size and location .”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “GISTs occurring in the duodenum and remainder of the small bowel can also demonstrate any growth pattern but are commonly exophytic, possibly explained by slow growth and often delayed presentations. Calcifications are uncommon but can occasionally be present within larger GISTs. When large, enhancement is often heterogeneous, and there can be large hypo-attenuating necrotic components. They can also be arterially hyper-enhancing.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “If a tumor is larger than 5 cm, and if removal would result in excessive damage to surrounding structures, it is typically considered unresectable. In these instances, treatment with targeted therapy (such as imatinib mesylate) is performed. Because mutational activation of TK receptors (KIT or PDGFRA) stimulates growth, targeted therapy agents are tyrosine kinase inhibitors, selectively blocking the GIST’s growth signal. Targeted therapy after surgical resection has become the standard of care to help prevent recurrence or treat recurrence or metastatic disease.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “Imaging evaluation of GISTs tumors using rapid reduction in size to indicate treatment response to target therapies can be used as in the Response Evaluation Criteria in Solid Tumors (RECIST) criteria . In these instances rapid decrease in tumor size and number of lesions has been described. However size criteria alone underestimates/misinterprets good response, as stable or initially increasing size has been described . FDG PET can increase accuracy of RECIST criteria by showing decreasing FDG-avidity over time.”
Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging Scola D, Bahoura L, Copelan A. et al. Abdom Radiol (2017) 42: 1350-1364 - “The most frequent clinical indication for imaging, which led to detection of the small bowel GISTs in our series, was suspected small bowel bleeding (45/111; 40.5%), with 34/45 of these patients having (75.5%) overt and 11/45 (24.5%) having occult small bowel bleeding. Abdominal pain was the indication for imaging in slightly over one-third of patients (41/111; 37%), with cancer surveillance in asymptomatic patients accounting for 9% (10/111) and clinical suspicion for potential small bowel tumor in 13% (15/111).”
Impact of CT enterography on the diagnosis of small bowel gastrointestinal stromal tumors Vasconcelos, R.N., Dolan, S.G., Barlow, J.M. et al. Abdom Radiol May 2017, Volume 42, Issue 5, pp 1365–1373
