An extramural gastrointestinal stromal tumor of the duodenum mimicking a pancreatic head tumor

A duodenal gastrointestinal stromal tumor mimicking a pancreatic neuroendocrine tumor: a case report

Background

Duodenal gastrointestinal stromal tumors are rare. If tumor growth is extraluminal and involves the head of the pancreas, the diagnosis of a duodenal gastrointestinal stromal tumor is difficult.

Case presentation

A 44-year-old Japanese woman was referred to our hospital with anemia. An enhanced computed tomography scan showed a hypervascular mass 30 mm in diameter, but the origin of the tumor, either the duodenum or the head of the pancreas, was unclear. Upper gastrointestinal endoscopy revealed bulging accompanied by erosion and redness in part of the duodenal bulb. Mucosal biopsy was not diagnostic. Endoscopic ultrasound fine-needle aspiration was difficult to perform because a pulsating blood vessel was present in the region to be punctured. These findings led to a diagnosis of pancreatic neuroendocrine tumor invasion to the duodenum. The patient underwent pancreaticoduodenectomy. Histologically, the tumor was made up of spindle-shaped cells immunohistochemically positive for c-Kit and CD34. The tumor was ultimately diagnosed as a duodenal gastrointestinal stromal tumor.

Conclusion

Extraluminal duodenal gastrointestinal stromal tumors are rare and mimic pancreatic neuroendocrine tumors. Endoscopic ultrasound fine-needle aspiration is useful for preoperative diagnosis, but it is not possible in some cases. Intraoperative diagnosis based on a completely resected specimen of the tumor may be useful for modifying the surgical technique.

Duodenal gastrointestinal stromal tumour imitating as pancreatic head tumour

Duodenal gastrointestinal stromal tumours (D-GISTs) are a rare disease. It may arise commonly from the second or third part of the duodenum and can be erroneously diagnosed as a pancreatic head tumour due to proximity and morphology on imaging studies. We present a case of a 60-year-old woman who presented with abdominal pain and was diagnosed as a case of pancreatic neuroendocrine tumour on radiologic imaging and granulomatous lesion on aspiration cytology. A ~5×3 cm mass was noted in the pancreatic head on laparotomy, and pancreatoduodenectomy was performed. Histopathology reported an exophytic GIST arising from the second part of the duodenum. Hence, D-GIST can invade the pancreas and mimic pancreatic head tumours; therefore, these tumours should be kept in the differential diagnosis of an atypical pancreatic head mass.

Outcome after Surgical Treatment of Gastrointestinal Stromal Tumors in the Second Part of Duodenum: Is Localized Resection Appropriate?

BACKGROUND

The second part of the duodenum is the most common part to be involved with duodenal gastrointestinal tumors (D2-GISTs). Localized resection (LR) and pancreaticoduodenectomy (PD) are two viable options for curative resection. The aim of this study is to compare the middle-term outcomes in patients with D2-GIST after either LR or PD in a single institution.

PATIENTS AND METHODS

Overall, 53 patients with non-metastatic D2-GIST were analyzed. Either LR or PD was executed depending on the involvement of the ampulla of Vater. The tumors were stratified in accordance with the Miettinen classification for tumor behavior. The patients were followed up for 3 years for recurrence and survival.

RESULTS

Thirty-two of the patients were females (60%) and 21 males (40%), with a mean age of 55 ± 8 years. Bleeding was the most common presentation in 19 patients (36%). LR was performed in 41 patients (77%), whereas PD was performed in 12 patients (23%). Three-year survival and recurrence were comparable between the two groups. The disease-free survival at 3 years was 85% and 92% in LR and PD group, respectively. The PD group had a significantly longer operative time and a higher incidence of postoperative pancreatic fistula. Otherwise, no statistically significant difference was calculated. A significantly shorter survival was calculated in those with a mitotic index of >5 and also for tumors classified as high grade in accordance with the Miettinen classification. 71% of those with recurrence had high mitotic index > 5/hpf.

CONCLUSIONS

LR for D2-GIST is an acceptable alternative to PD with satisfactory middle-term outcomes. For tumors involving the ampulla of Vater, PD is still indicated. Furthermore, tumor biology predicts the likelihood of survival and recurrence.

Differentiation of duodenal gastrointestinal stromal tumors from hypervascular pancreatic neuroendocrine tumors in the pancreatic head using contrast-enhanced computed tomography

PURPOSE

To determine useful contrast-enhanced computed tomography (CE-CT) features in differentiating duodenal gastrointestinal stromal tumors (duodenal GISTs) from hypervascular pancreatic neuroendocrine tumors in the pancreatic head (pancreatic head NETs).

METHODS

Seventeen patients with pathologically confirmed duodenal GISTs and 25 with pancreatic NETs underwent preoperative CE-CT. CT image analysis included tumor size, morphology, and contrast enhancement. Receiver operating characteristic curves were performed, and cutoff values were calculated to determine CT findings with high sensitivity and specificity.

RESULTS

CT imaging showed duodenal GISTs with higher frequencies of tumor central location close to the duodenum and a predominantly solid tumor type when compared with pancreatic head NETs (p < 0.05 for both). Duodenal GISTs were larger than pancreatic head NETs (3.3 ± 0.9 cm vs. 2.5 ± 1.1 cm, p = 0.03). Duodenal GISTs had significantly lower CT attenuation values (112.9 ± 17.9HU vs. 137.4 ± 32.1HU, p < 0.01) at the arterial phase and higher CT attenuation values at the delayed phase (94.3 ± 7.9HU vs. 84.9 ± 10.4HU, p < 0.01) when compared with pancreatic head NETs. A CT attenuation value of ≤ 135 HU at the arterial phase (30 s) was 76% sensitive, 94.1% specific, and 83.3% accurate for the diagnosis of duodenal GISTs, while a CT attenuation value of ≥ 89.5 HU at the delayed phase (120 s) was 93.3% sensitive, 81.8% specific, and 76.2% accurate for the diagnosis of duodenal GISTs.

CONCLUSION

Tumor central location, size, texture, and contrast enhancement are valuable characteristics for the differentiation between duodenal GISTs and hypervascular pancreatic head NETs during preoperative examination.

Pancreatic extragastrointestinal stromal tumor invading the duodenum

Extragastrointestinal stromal tumors that arise in the pancreas are extremely rare and managing them can be difficult, particularly if located in the head of pancreas. This case report aims to contribute to the existing data in the literature regarding extragastrointestinal stromal tumors with rare and unusual locations. We present a 56-year-old man who presented with recurrent mild right upper quadrant abdominal pain. Abdominal computed tomography and magnetic resonance imaging revealed a mass lesion with a diameter of 10 cm localized in the head of pancreas. Pancreaticoduodenectomy with complete tumor excision was performed. He was discharged on the postoperative day 14. Only 15 extragastrointestinal stromal tumors cases have been reported. Of these 15 cases, tumors were located in the head of pancreas in six cases. Here we report the seventh case of pancreatic extragastrointestinal stromal tumor arising in the head of pancreas and also the largest of these seven tumors.

Surgical treatment of gastrointestinal stromal tumors of the duodenum: a literature review

Background

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumours in the digestive tract. The duodenal GIST (dGIST) is the rarest subtype, representing only 4-5% of all GIST, but up to 21% of the resected ones. The diagnostic and therapeutic management of dGIST may be difficult due to the rarity of this tumor, its anatomical location, and the clinical behavior that often mimic a variety of conditions; moreover, there is lack of consent for their treatment. This study has evaluated the scientific literature to provide consensus on the diagnosis of dGIST and to outline possible options for surgical treatment.

Methods

An extensive research has been carried out on the electronic databases MEDLINE, Scopus, EMBASE and Cochrane to identify all clinical trials that report an event or case series of dGIST.

Results

Eighty-six studies that met the inclusion criteria were identified with five hundred forty-nine patients with dGIST: twenty-seven patients were treated with pancreatoduodenectomy and ninety-six with only local resection (segmental/wedge resections); in four hundred twenty-six patients it is not possible identify the type of treatment performed (pancreatoduodenectomy or segmental/wedge resections).

Conclusions

dGISTs are a very rare subset of GISTs. They may be asymptomatic or may involve symptoms of upper GI bleeding and abdominal pain at presentation. Because of the misleading clinical presentation the differential diagnosis may be difficult. Tumours smaller than 2 cm have a low biological aggressiveness and can be followed annually by endoscopic ultrasound. The biggest ones should undergo radical surgical resection (R0). In dGIST there is no uniformly adopted surgical strategy because of the low incidence, lack of experience, and the complex anatomy of the duodenum. Therefore, individually tailored surgical approach is recommended. R0 resection with 1-2 cm clear margin is required. Lymph node dissection is not recommended due to the low incidence of lymphatic metastases. Tumor rupture should be avoided.

Clinicopathological features, surgical strategy and prognosis of duodenal gastrointestinal stromal tumors: a series of 300 patients

BACKGROUND

The relatively low incidence of duodenal gastrointestinal stromal tumors (GISTs) and the unique anatomy make the surgical management and outcomes of this kind of tumor still under debate. Thus, this study aimed to explore the optimal surgical strategy and prognosis of duodenal GISTs.

METHODS

A total of 300 cases of duodenal GISTs were obtained from our center (37 cases) and from case reports or series (263 cases) extracted from MEDLINE. Clinicopathological features, type of resections and survivals of duodenal GISTs were analyzed.

RESULTS

The most common location of duodenal GISTs was descending portion (137/266, 51.5%). The median tumor size was 4 cm (0.1-28). Most patients (66.3%) received limited resection (LR). Pancreaticoduodenectomy (PD) was mainly performed for GISTs with larger tumor size or arose from descending portion (both P < 0.05). For both the entire cohort and tumors located in the descending portion, PD was not an independent risk factor for disease-free survival (DFS) and disease-specific survival (DSS) (both P > 0.05). Duodenal GISTs were significantly different from gastric GISTs with respect to tumor size, mitotic index and NIH risk category (all P < 0.05). The DFS and DSS of duodenal GISTs was significantly worse than that of gastric GISTs (both P < 0.05).

CONCLUSIONS

LR was a more prevalent surgical procedure and PD was mainly performed for tumors with larger diameter or located in descending portion. Type of resection was not an independent risk factor for the prognosis of duodenal GISTs. Prognosis of duodenal GISTs was significantly worse than that of gastric GISTs.

Paraduodenal pancreatitis: benign and malignant mimics at MRI

Paraduodenal pancreatitis, also known as groove pancreatitis, is a rare form of chronic pancreatitis that masquerades as pancreatic adenocarcinoma affecting the pancreaticoduodenal groove, a potential space between the head of the pancreas, duodenum, and common bile duct. Two forms of groove pancreatitis have been described. The segmental form involves the pancreatic head with development of scar tissue within the groove, whereas the pure form affects the groove only, sparing the pancreatic head. Imaging findings of groove pancreatitis often overlap with primary duodenal, ampullary, or pancreatic neoplasms, which often results in a diagnostic challenge. In addition, paraduodenal pancreatitis can be mistaken for cystic pancreatic lesions, especially when there is involvement of the duodenal wall. Preoperative recognition of this entity is very important in order to avoid unnecessary procedures, although surgery, such as pancreaticoduodenectomy, may still be required to relieve obstructive symptoms. In this article, the pathophysiology and magnetic resonance imaging characteristics of paraduodenal pancreatitis and important benign and malignant mimics are discussed.

Surgical Strategy and Outcomes in Duodenal Gastrointestinal Stromal Tumor

BACKGROUND

The surgical management of duodenal gastrointestinal stromal tumors (DGIST) is poorly characterized. Limited resection may be technically feasible and oncologically safe, but anatomic considerations may compromise the resection margins due to the proximity of critical structures, thereby necessitating more extensive resections such as pancreaticoduodenectomy.

METHODS

Patients undergoing surgery for DGIST at two institutions from 1994 to 2014 were identified. Clinicopathologic and survival data were analyzed to compare outcomes in patients treated with limited or radical resection.

RESULTS

Sixty patients underwent surgery for DGIST. Pancreaticoduodenectomy was performed in 38 % while the rest underwent limited resections. The most common type of limited resection was wedge resection and primary closure (49 %) followed by segmental resection with an end-to-end or side-to-side duodenojejunostomy (27 %). The pancreaticoduodenectomy group tended to have larger tumors with the majority located in D2/3 (87 %) and at the mesenteric border (91 %). The pancreaticoduodenectomy group also had significantly greater intraoperative blood loss, longer operative time, longer hospital stay, and higher 90-day morbidity and readmission rates. The 5-year relapse-free survival, recurrence-free survival, and overall survival for the pancreaticoduodenectomy versus limited resection were 81 versus 56 % (p = 0.05), 64 versus 53 % (p = 0.5), and 76 versus 72 % (p = 0.6), respectively. A surgical algorithm based on the location and size of the tumor is proposed.

CONCLUSIONS

Limited resection of DGIST is safe, but may be associated with lower 5-year relapse-free survival. Pancreaticoduodenectomy is recommended for selected patients with DGIST when an R0 resection cannot be performed without removing the ampulla or part of the pancreas.

Limited resections for duodenal gastrointestinal stromal tumors and their oncologic outcomes

PURPOSE

Limited resection is considered a treatment option for duodenal gastrointestinal stromal tumors (GISTs) whenever technically feasible, but the optimal technique for this is still not well defined. We present the various types of limited resections for duodenal GISTs and analyze their postoperative outcomes.

METHODS

The subjects of this retrospective clinicopathologic analysis were 21 patients who underwent limited resections for duodenal GIST between May, 2001 and June, 2014. The median follow-up period was 52 months (range 5-125 months).

RESULTS

The patients comprised 12 men and 9 women, with a median age of 59 years (range 45-75 years), all of whom were treated by various forms of limited resection with clear margins. There were ten wedge resections with primary closure (eight open/two laparoscopic), two wedge resections with Roux-en Y duodenojejunostomy, three segmental duodenectomies with end-to-end duodenoduodenostomy, and six segmental duodenectomies with end-to-end duodenojejunostomy. Hepatic metastasis was found 27 months after surgery in one patient, who was given imatinib mesylate for 17 months to slow disease progression. The other 20 patients were alive and recurrence free at the time of writing.

CONCLUSION

Excellent recurrence-free survival was achieved after limited resections, supporting the consideration of various methods of limited resection as the treatment of choice for duodenal GISTs.

Easy to swallow: detection of an extramural jejunal GIST by video capsule endoscopy

We report a case of a 57-year-old woman with an obscure gastrointestinal bleed who was found to have an extramural gastrointestinal stromal tumour (GIST), detected by capsule endoscopy, and confirmed by laparoscopically-assisted enteroscopy and resection. Currently, major modalities used for detection of GISTs include double-balloon enteroscopy, capsule endoscopy and CT. Endoscopic measures, including capsule endoscopy, are limited in their ability to detect GISTs with extramural growth, as these typically do not demonstrate obvious luminal abnormalities. This case report illustrates a case in which an extraluminal GIST causing recurrent gastrointestinal bleeding presented as an ulcer, as seen on capsule endoscopy.

Duodenal gastrointestinal stromal tumor: From clinicopathological features to surgical outcomes

Duodenal gastrointestinal tumors represent an extremely rare subset of stromal tumors arising from interstitial cells of Cajal. In the last 30 years the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity, in association with developments in endoscopy, imaging technology, and immunohistochemistry has resulted in novel diagnostic and treatment approaches. This is a comprehensive review of the current data of the literature on the various aspects of the diagnosis and treatment of these tumors. The duodenum is the less commonly involved site for these tumors in the digestive tract. Endoscopy and computed tomography can usually establish the diagnosis, confirmed by immunohistochemical staining and occasionally molecular genetic analysis. Endoscopic ultrasound with fine needle aspiration has been recently found to be the gold diagnostic standard with high sensitivity and specificity rates, diagnosing GIST in up to 80% of patients. Due to the complex anatomy of the pancreatico-duodenal region optimal therapeutic strategy of duodenal GISTs are challenging. Nevertheless surgical resection with microscopically clear resection margins seems to be the only potentially curative treatment for non-metastatic primary GISTs of the duodenum. Imatinib mesylate plays a key role in the management of GISTs both as neoadjuvant therapy and in patients with recurrent and metastatic disease. Meanwhile, the advances in the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity as well as the treatment of these tumors may render feasible, in the near future, the advent of newer and more effective treatment options.

Duodenal gastrointestinal stromal tumors: review on clinical and surgical aspects

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) arising in the duodenum represent a rare entity and can be very demanding to manage. The diagnosis can be difficult (as these tumors can be misdiagnosed as pancreatic head tumors), and to treat owing to the complex anatomy of the duodenum and of the pancreatic head. Complete resection may require extensive procedures such as pancreaticodudodenectomy.

METHODS AND RESULTS

An extensive literature review regarding clinico-pathological features, diagnostic investigations and surgical options in the management of duodenal GISTs has been performed.

CONCLUSIONS

Duodenal GISTs have uncertain malignant potential, and they may be asymptomatic, or present with abdominal pain or bleeding. A preoperative diagnosis can be difficult to obtain. Endoscopic ultrasound and fine needle aspiration cytology (FNAC) may be helpful. Surgical R0 resection remains the only curative approach. However, owing to the complex anatomy of the duodenum, limited resection is not always feasible. In these cases, extensive procedures such as pancreaticoduodenectomy or pancreas-preserving duodenectomy are the treatment of choice.

A large gastrointestinal stromal tumor of the duodenum: a case report

Introduction

Gastrointestinal stromal tumors of the duodenum are uncommon. They can reach a large size. Diagnosis can be elusive and managing them can be difficult. Our case report aims to increase awareness and highlight some issues related to the diagnosis and management of duodenal gastrointestinal stromal tumors.

Case presentation

We present the case of a 38-year-old Middle Eastern woman with a large, slowly-growing gastrointestinal stromal tumor of the duodenum. Her complaints were minor epigastric discomfort and swelling. A pancreaticoduodenectomy with complete tumor excision was performed. She was doing very well with no evidence of disease recurrence when she was last seen 34 months after her operation.

Conclusion

Gastrointestinal stromal tumors of the duodenum should be suspected in any patient with a duodenal wall mass. Extramural growth and central ulceration with or without bleeding should alert the endoscopist to the possibility of a duodenal gastrointestinal stromal tumor diagnosis. There is more than one surgical approach available; however, complete surgical excision, with negative margins, is the absolute requirement. Preoperative imatinib mesylate can be considered in unresectable or borderline resectable cases.

Segmental duodenectomy with duodenojejunostomy of gastrointestinal stromal tumor involving the duodenum

Duodenal gastrointestinal stromal tumors (GISTs) are uncommon and a relatively small subset of GISTs whose optimal surgical procedure has not been well defined. Because submucosal spread and local lymph node involvement is infrequent in GISTs, wide margins with routine lymph node dissection may not be required. Various techniques of limited resection for duodenal GISTs have been described depending on the site and the size of the tumors. In this study, we report two cases of GIST involving the third and fourth portion of the duodenum successfully treated by segmental duodenectomy with end-to-end duodenojejunostomy. This technique should be considered as a treatment option for GIST located at the third and fourth portion of the duodenum.

Duodenal gastrointestinal stromal tumor resembling a pancreatic neuroendocrine tumor in a patient with neurofibromatosis type I (von Recklinghausen's disease): a case report

Introduction

Gastrointestinal stromal tumor is the most frequent nonepithelial tumor found in the gastrointestinal tract. One important clinical problem is that gastrointestinal stromal tumors, especially the extramural growth type, can be difficult to distinguish from other organ tumors. The case of a patient with an extramural gastrointestinal stromal tumor of the duodenum that mimicked a pancreatic head tumor has previously been reported. Here, we report a rare case of a patient with a duodenal gastrointestinal stromal tumor with extramural growth that mimicked a pancreatic neuroendocrine tumor. In this case, the gastrointestinal stromal tumor was also associated with neurofibromatosis type 1 (also known as von Recklinghausen's disease). To the best of our knowledge, this is the first report to describe the case of a patient with a duodenal gastrointestinal stromal tumor with neurofibromatosis type 1 in which the radiological findings resembled those of a pancreatic neuroendocrine tumor.

Case presentation

A 60-year-old Japanese woman with a history of neurofibromatosis type 1 was admitted to our hospital for the treatment of a tumor of her pancreas. She had no symptoms, but an abdominal ultrasonography screening examination had revealed a hypoechoic mass in the head of her pancreas. Laboratory data, including tumor markers, were within the normal ranges, and her insulin and glucagon levels were also within the normal ranges. However, her plasma gastrin level was elevated at 580 pg/mL (30 to 150 pg/mL). A computed tomography examination revealed a hypervascular tumor measuring 14 mm in diameter in the head of her pancreas. We diagnosed the patient as having a pancreatic neuroendocrine tumor and performed a tumor resection with a duodenal wedge resection. Microscopic analysis revealed spindle cell tumors in a trabecular pattern. The patient was finally diagnosed as having a duodenal gastrointestinal stromal tumor of the uncommitted type.

Conclusion

Extramural growth-type gastrointestinal stromal tumors can be difficult to distinguish from other organ tumors. In our case, a duodenal gastrointestinal stromal tumor was difficult to distinguish from a pancreatic neuroendocrine tumor based on radiological findings. When patients are identified as having hypervascular lesions that have adhered to the gastrointestinal tract, the possibility of an extramural growth-type gastrointestinal stromal tumor as a differential diagnosis should be considered in patients with neurofibromatosis type 1.

Management and outcome of gastrointestinal stromal tumors of the duodenum

BACKGROUND

Duodenal gastrointestinal stromal tumors (GISTs) are uncommon and relatively small subset of GISTs whose optimal surgical procedure has not been well defined. We conducted this study to present the surgical experience in our institution and to analyze the postoperative outcome of duodenal GISTs.

METHODS

A retrospective clinicopathologic analysis was performed for nine duodenal GIST patients who underwent surgery from May 2001 to April 2009. The median follow-up period was 22 months (range: 13-61 months).

RESULTS

A total of nine patients (six males/three females) with a median age of 52 years (range: 45-73 years) were treated. The most common presentation was abdominal pain (45%), and the second portion of duodenum (45%) was most common dominant site. All of the patients underwent limited resection: there were seven wedge resections with primary closures (five open/two laparoscopic) and two segmental resections with end-to-end duodenojejunostomies. The median tumor size was 3.5 cm (range: 1.9-5.5 cm), and the mitotic count was less than fivemitoses/50 high power fields (HPF) in all cases. None patients had neoadjuvant or adjuvant therapy. All of the patients were alive and disease-free.

CONCLUSION

We obtained excellent disease-free survival following limited resection with clear margins. Limited resection should be considered a treatment option for duodenal GIST.

Stromal duodenal tumor revealed by an acute pancreatitis: report of a case

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) are one of the most common mesenchymal neoplasms of the human gastrointestinal tract. Duodenal GISTs are very rare and constitute less than 5% of all kind of GISTs.

CASE REPORT

This is a report of a rare gastrointestinal stromal tumor of the duodenum in a 25-year-old female who was presented as an acute pancreatitis.

DISCUSSION

The computed tomography evoked a pancreatic tumor. The patient underwent successful Whipple's procedure. The histological and immunohistochemical exams of the specimen resection confirmed the diagnosis of duodenal stromal tumor.

Segmental resection of the duodenum for gastrointestinal stromal tumor (GIST)

BACKGROUND

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumors of the gastrointestinal tract. The biological appearance of these tumors reaches from small lesions with benign appearance to aggressive sarcomas. Only 3-5% of GISTs are localized in the duodenum. There is a controversy, if duodenal GISTs should be treated by a duodenopancreatectomy or by a limited resection of the duodenum.

CASE PRESENTATION

A 29-year-old man presented with an acute upper gastrointestinal bleeding from a submucosal tumor located in the proximal part III of the duodenum, 3 cm distal of the papilla of Vater. After an emergency laparotomy with ligation of tumor-feeding vessels in a primary hospital, definitive surgical therapy was performed by partial resection of the duodenum with a duodenojejunostomy. Histology revealed a GIST with a diameter of 2.5 cm and <5 mitoses/50 high power fields, indicating a low risk of malignancy. Therefore no adjuvant therapy with Imatinib was initiated.

CONCLUSION

GISTs of the duodenum are a rare cause of upper gastrointestinal bleeding. Partial resection of the duodenum is a warranted alternative to a duodenopancreatectomy, as this procedure has a lower operative morbidity, while providing comparable oncological results.

Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis

Over the last decade, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure gastrointestinal mesenchymal tumors to well-defined tumors with distinctive clinical, morphologic, ultrastructural, histogenetic, and molecular characteristics, for which targeted therapy is available. This is largely attributable to the discovery of CD117 overexpression and activating mutations in c-kit or platelet-derived growth factor alpha genes in most of GISTs. The availability of specific diagnostic tests and targeted therapy for GISTs has led to an increased awareness of these tumors. At the same time, the list of potential GIST mimics has lengthened considerably and it has become increasingly important that GISTs be distinguished from their mimics because correct diagnosis has implications for both treatment and prognosis. The purpose of this review is to provide an update of the expanding differential diagnosis of GISTS, to draw attention to unusual GIST variants, to provide a practical approach the differential diagnosis of GISTs and to highlight some of the challenges faced by pathologists in resolving this differential diagnosis.

A gastrointestinal stromal tumor of the duodenum masquerading as a pancreatic head tumor

Gastrointestinal stromal tumor (GIST) represents the most common kind of mesenchymal tumor that arises from the alimentary tract. GIST is currently defined as a gastrointestinal tract mesenchymal tumor showing CD117 (c-kit protein) positivity at immunohistochemistry. Throughout the whole length of the gastrointestinal tract, GIST arises most commonly from the stomach followed by the small intestine, the colorectum, and the esophagus. Only 3%-5% of GISTs occur in the duodenum, and especially, if GIST arises from the C loop of the duodenum, it can be difficult to differentiate from the pancreas head mass because of its anatomical proximity. Here, we report a case of duodenal GIST, which was assessed as a pancreatic head tumor preoperatively.

Late hemorrhage after pancreatoduodenectomy and heavy ion beam therapy

The patient was a 57-year-old man diagnosed with cancer of the pancreatic head. After treatment by heavy ion beam therapy, pylorus-preserving pancreatoduodenectomy was performed. The tumor was pT3, pN0, pM0, stage IIA. Sixteen months after the surgery, the patient was admitted to the hospital because he was vomiting blood. Hemorrhaging caused by failure of the cut end of the gastroduodenal artery into the elevated jejunum was confirmed by angiogram, and the hemorrhaging could be stopped by a transcatheter arterial embolization operation. Twenty-four months after surgery, the patient was readmitted because he was once again vomiting blood. Hemorrhaging from the elevated jejunum was suspected by hemorrhagic scintigram, but the source could not be identified on further examination, and the choice of treatment was difficult. The patient died on the 9th day after admittance to the hospital. Even on examination at autopsy, the source of the hemorrhaging could not be identified. No recurrence of cancer could be found. This has proven to be a perplexing case, in that hemorrhaging from the end of the routinely cut gastroduodenal artery occurred 16 and 24 months after heavy ion beam therapy and pylorus-preserving pancreatoduodenectomy for pancreatic cancer.