Gastrointestinal stromal tumors and leiomyosarcomas in the colon: a clinicopathologic, immunohistochemical, and molecular genetic study of 44 cases

Esterase-Responsive Polyglycerol-Based Nanogels for Intracellular Drug Delivery in Rare Gastrointestinal Stromal Tumors

Rare gastrointestinal stromal tumors (GISTs) are caused by mutations in the KIT and PDGFRA genes. Avapritinib (BLU-285) is a targeted selective inhibitor for mutated KIT and PDGFRA receptors that can be used to treat these tumors. However, there are subtypes of GISTs that exhibit resistance against BLU-285 and thus require other treatment strategies. This can be addressed by employing a drug delivery system that transports a combination of drugs with distinct cell targets. In this work, we present the synthesis of esterase-responsive polyglycerol-based nanogels (NGs) to overcome drug resistance in rare GISTs. Using inverse nanoprecipitation mediated with inverse electron-demand Diels-Alder cyclizations (iEDDA) between dPG-methyl tetrazine and dPG-norbornene, multi-drug-loaded NGs were formed based on a surfactant-free encapsulation protocol. The obtained NGs displayed great stability in the presence of fetal bovine serum (FBS) and did not trigger hemolysis in red blood cells over a period of 24 h. Exposing the NGs to Candida Antarctica Lipase B (CALB) led to the degradation of the NG network, indicating the capability of targeted drug release. The bioactivity of the loaded NGs was tested in vitro on various cell lines of the GIST-T1 family, which exhibit different drug resistances. Cell internalization with comparable uptake kinetics of the NGs could be confirmed by confocal laser scanning microscopy (CLSM) and flow cytometry for all cell lines. Cell viability and live cell imaging studies revealed that the loaded NGs are capable of intracellular drug release by showing similar IC50 values to those of the free drugs. Furthermore, multi-drug-loaded NGs were capable of overcoming BLU-285 resistance in T1-α-D842V + G680R cells, demonstrating the utility of this carrier system.

[Rectal leiomyosarcoma, a rare malignant tumor diagnosed in ulcerative colitis]

Patients with chronic inflammatory diseases (IBD) of the digestive tract are known to have an increased risk of colorectal cancer. These are usually adenocarcinomas, and the occurrence of malignant mesenchymal tumours, particularly leiomyosarcomas, is exceptional. We report one case in a 40-year-old woman, followed for 9 years for ulcerative colitis. The tumour measured 2cm in length and infiltrated the entire rectal wall as far as the subserosa. It was composed of fusiform cells, with 5 mitoses for 10 fields at ×400 magnification, and expressing actin, desmin and caldesmone under immunohistochemical study. We review the 2 cases of leiomyosarcomas associated with Crohn's disease and 3 cases developed during ulcerative colitis published in the literature.

Clinicopathological features and prognosis of colonic and rectal gastrointestinal stromal tumors: A propensity score matching analysis

Background

Colonic gastrointestinal stromal tumor (cGIST) and rectal gastrointestinal stromal tumor (rGIST) are two rare subtypes of gastrointestinal stromal tumor (GIST). The view that colonic and rectal carcinoma are different is generally accepted; however, whether there is a difference between cGIST and rGIST is still unknown. Here, we aimed to provide evidence for future clinical management and research by comparing the differences between the two types of GIST in the above-mentioned aspects.

Methods

Patients were enrolled from three medical centers in China and published literature was collected following the inclusion and exclusion criteria. Propensity score matching was used to eliminate differences between cohorts.

Results

Between cGIST and rGIST patients, significant differences were observed in age, tumor size, mitotic index, NIH risk category, growth pattern, and symptoms. Adjuvant therapy is used in a high proportion of cGIST patients, and neoadjuvant therapy is used in a high proportion of rGIST patients. Although local resection is the main surgical method in both cohorts, the proportion is higher in cGIST patients. The overall survival of rGIST patients was better than that of the cGIST patients before propensity score matching (PSM). Interestingly, no significant differences in prognosis were observed after PSM.

Conclusions

Although there were significant differences between cGIST and rGIST patients in baseline characteristics, clinicopathological features, treatment choice, and overall survival rate before PSM, no significant differences in long-term survival were observed between the two groups after PSM. In our study, there may be no differences in the tumor entity between cGIST and rGIST.

Gastrointestinal stromal tumors (GISTs) arising in uncommon locations: clinicopathologic features and risk assessment of esophageal, colonic, and appendiceal GISTs

Risk stratification of gastrointestinal stromal tumors (GISTs) is based on experience with tumors of the stomach, small bowel, and rectum, which are far more common than GISTs of other sites. In this study from 47 institutions, we analyzed GISTs of the esophagus (n = 102), colon (n = 136), and appendix (n = 27) for their size, mitotic rate, morphology, and outcome to determine which criteria predict their behavior. Esophageal GISTs were small (median: 2.5 cm) with spindle cell morphology and a low mitotic rate (mean: 3.6/5 mm²). Twelve (12%) tumors progressed, including 11 with a mitotic rate >5/5 mm² and one large (6.8 cm) GIST with a mitotic rate of 2/5 mm². Colonic GISTs were smaller (median: 1.4 cm) and presented with abdominal pain or bleeding in 29% of cases. Most (92%) were composed of spindle cells with a mean mitotic rate of 4.6/5 mm². Sixteen (12%) tumors progressed: 14 had mitotic rates >5/5 mm², and two were >5.0 cm with a mitotic rate <5/5 mm². All but one appendiceal GIST measured <2.0 cm. These tumors were composed of spindle cells with low mitotic rates (<5/5 mm²), and none progressed. Our results suggest that progression risk among esophageal and colonic GISTs is associated with increased mitotic activity (>5/5 mm²) and size >5.0 cm. These findings support the use of size and mitotic rate for prognostication of GISTs in these locations, similar to tumors of the stomach, small bowel, and rectum.

Primary duodenal dedifferentiated liposarcoma: A case report and literature review

BACKGROUND

Dedifferentiated liposarcoma (DDLPS) is an extremely rare neoplasm that exhibits various morphologies. The tumor is characterized by immunoreactivity to MDM2 and CDK4 and can be confirmed by detecting MDM2 amplification via fluorescence in situ hybridization (FISH). Herein, we report an unusual case of DDLPS arising from the duodenum.

CASE SUMMARY

A 64-year-old man presented with repeated abdominal pain and weight loss. Radiologic studies revealed a mass of the duodenum involving the pancreas. The patient was treated with pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor showed a high-grade sarcoma. Immunohistochemistry demonstrated that the tumor cells were positive for MDM2 and CDK4 expression. MDM2 amplification was detected via FISH, leading to the final diagnosis of DDLPS. Following surgery, the patient was treated in the intensive care unit due to peritonitis, and died 60 d after surgery.

CONCLUSION

To the best of the authors’ knowledge, this is the first case of primary duodenal DDLPS in Korea and the third case in the English-language literature. Care must be taken not to misdiagnose DDLPS as another high-grade tumor. Liposarcoma should be in the differential diagnosis list.

Prognostic Factors in Gastrointestinal Leiomyosarcomas: An Analysis Using the Surveillance, Epidemiology, and End Results (SEER) Database

Background Gastrointestinal leiomyosarcomas (LMSs) from intramural smooth muscle are extremely rare, with limited literature. This paper evaluates the epidemiology and survival and prognostic factors in LMSs of the gastrointestinal tract. Methods Clinical data from the Surveillance, Epidemiology and End Results (SEER) 18 registry from 2001 to 2016 with additional treatment fields were compared between primary tumor sites using the chi-squared test for categorical variables and ANOVA for continuous variables. A five-year survival rate analysis was performed for overall and cancer-specific survival. Hazard ratios (HRs) were calculated using univariate and multivariate Cox proportional models using the variables age group, tumor location, grade, stage, surgery, and chemotherapy. Results We identified a total of 523 patients diagnosed with LMSs of the gastrointestinal tract. The median age of diagnosis was 66 years, with no significant difference between tumor sites for age, sex, and race. The five-year overall survival was 77.3%, and the cancer-specific survival was 90.3%. In the multivariate analysis, grade and stage of tumor were the only factors significantly affecting survival in this cohort. Conclusion While surgical status significantly affected survival in the univariate analysis, when adjusted for other factors, the HR for death was not significantly different by surgical therapy. Grade 3 tumors and tumors with distant metastasis at diagnosis were associated with worse survival among these patients.

Malignant Degeneration to Leiomyosarcoma of the Anorectal Junction Invading the Prostate

While colonic leiomyomas are common, leiomyosarcomas of the GI tract are rare. Increased mitotic rate, as well as lymph node involvement, portend a worse prognosis in leiomyosarcomas. They can arise anywhere along the GI tract, but anal canal occurrence is extremely rare. We present the case of a 75-year-old male diagnosed eight years prior with leiomyoma of the anorectal junction. There was a recurrence after endoscopic resection. He was referred to colorectal surgery due to symptoms of bleeding, skin irritation, anal pruritus, and rectal pain. On exam, he had a palpable mass at the dentate line. Workup revealed a 3.5 cm mass at the anorectal junction with pathology showing a leiomyosarcoma with moderate atypia and a high mitotic rate. MRI revealed invasion into the prostate. Robotic pelvic exenteration, including cystoprostatectomy, abdominoperineal resection, and ileal conduit, was performed. Final pathology results showed a grade 2 leiomyosarcoma invading the prostate and skeletal muscle and incidentally found Gleason 3+4 prostate cancer, pT2.  A very small percentage of anorectal leiomyosarcoma cases were located in the anal canal. Surgery remains the best curative option, as chemotherapy and radiation data are limited. This rare tumor, which previously has not been documented to have degenerated from a benign rectal leiomyoma, was diagnosed as a result of close monitoring after previous local resections and cured by local resection and radiation.

Two cases of primary leiomyosarcoma of sigmoid colon treated with laparoscopic surgery: A case report and a review of literature

INTRODUCTION AND IMPORTANCE

Leiomyosarcoma (LMS) of the colon is an extremely rare and highly invasive tumor arising from the muscularis propria of the gastrointestinal tract. After the introduction of oncogenic role of KIT by immunohistochemistry (IHC), the reported cases of gastrointestinal leiomyosarcoma were highly limited. True LMS of the colon is such a rare disorder that there isn't much description of its nature.

CASE PRESENTATION

We reported two very rare cases of primary leiomyosarcoma of sigmoid colon, which referred to our institution with symptoms of abdominal pain, lower GI bleeding and fatigue. After the initial investigations, both patients were diagnosed with primary LMS of sigmoid colon that underwent laparoscopic tumor resection.

CLINICAL DISCUSSION

The classical colonic LMS presents with a vast majority of non-specific symptoms including mild abdominal pain, fresh/obscure rectal bleeding, and weight loss. The most common location for colonic LMS is the sigmoid colon, and ascending colon. The prognostic factors for the disease outcome have not been established properly; however, patient age, tumor size/grade, and local/distant dissemination are of great importance.

CONCLUSION

Herein, we reported two rare cases of primary leiomyosarcoma of sigmoid colon that was treated with laparoscopic surgery.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Gastrointestinal Stromal Tumor as a Rare Cause of Abdominal Mass: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas that can arise from any part of the digestive system. GISTs represent 1% of gastric neoplasms. We report a rare case of a GIST tumor in a 59-year-old woman who presented with abdominal pain and weight loss. Computed tomography (CT) of the abdomen with intravenous contrast revealed a left upper quadrant abdominal mass and biopsy showed GIST. She was treated with imatinib to downsize the tumor prior to undergoing surgical resection of the tumor.

A case of planar-type gastrointestinal stromal tumor of the transverse colon with perforation

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the human gastrointestinal tract. They usually develop in the stomach and small intestine, but extremely rarely in the colon. Although most GISTs form a mass, some cases showing a flatly proliferating lesion called planar-type GIST have been reported in the sigmoid colon and small intestine. Those are often associated with diverticular lesion and/or perforation. We present here a case of planar-type GIST of the transverse colon with perforation. A 49-year-old Japanese woman abruptly complained of abdominal pain, and was clinically diagnosed as perforation of the transverse colon. Partial resection of the transverse colon including the perforated site was done, and no apparent mass lesion was present. Histology showed that spindle cells flatly proliferated around the perforated area and replaced the layers from submucosa to subserosa. Immunohistochemistry revealed that the spindle cells were KIT-, DOG1- and CD34-positive. Codons 557 and 558 of exon 11 of the c-kit gene were heterozygously deleted at the lesional tissue but not at the normal mucosal tissue. Planar-type GIST of the transverse colon has not been reported yet, and the literature search for the similar cases was done.

Leiomyosarcoma of the transverse colon with lymph node metastasis and malignant transformation: a case report

Background

The concept of GIST was established in 1998, clearly differentiating between gastrointestinal leiomyosarcoma and GISTs among gastrointestinal mesenchymal tumors. Lymph node metastasis is extremely rare in true gastrointestinal leiomyosarcoma, and there are no reports of malignant transformation from leiomyoma.

Case presentation

The patient was an old woman who had undergone endoscopic mucosal resection for an Is polyp on the left side of the transverse colon at the age of 73. She was diagnosed with leiomyoma with positive surgical margins. Subsequently, she presented to our institution with a sensation of pressure in the upper abdominal region as a chief complaint at the age of 76 years. Abdominal computed tomography and colorectal endoscopy showed a tumor lesion with invagination of the intestines in the transverse colon, the same site as that of the previously resected leiomyoma. A biopsy suggested a smooth muscle tumor, and we performed partial left transverse colectomy and lymph node dissection under a diagnosis of recurrence and enlargement of the previously incompletely resected leiomyoma. Histopathological examination revealed spindle-shaped tumor cells, and the mitotic activity was 30–40/10 high-power field. Tumor cells were immunohistologically positive for α-smooth muscle actin and h-caldesmon; partially positive for desmin; negative for c-kit, CD34, DOG-1, and the S-100 protein; and showed a Ki-67 labeling index of 70–80%. She was diagnosed with leiomyosarcoma malignantly transformed from leiomyoma. Metastasis was found in 1 of the 14 resected lymph nodes. The patient did not undergo adjuvant chemotherapy, but has survived with no recurrence at 2 years after the surgery.

Conclusions

We have reported a case of leiomyosarcoma of the transverse colon with lymph node metastasis that was malignantly transformed from a leiomyoma.

Primary leiomyosarcoma of the colon: a case report and review of the literature

Introduction: Primary leiomyosarcoma (LMS) of the colon is a rare and aggressive gastrointestinal tract tumor, associated with poor prognosis.Case presentation and methods: We present the case of an asymptomatic patient who was diagnosed with a low sigmoidal stricture on routine colonoscopy. Although biopsies were inconclusive, an oncological partial mesorectal excision (PME) was performed due to the malignant macroscopic aspect. Pathological examination surprisingly revealed a LMS. The patient received no adjuvant chemo- or radiotherapy, but is seen on regular follow-up. We review the literature on leiomyosarcoma of the colon: its diagnosis, treatment, and prognosis.Results: Up until now the patient shows no sign of recurrence, 15 months postoperatively.Conclusion: Radical resection is the treatment of choice for primary leiomyosarcoma of the colon and long-term follow-up is needed to evaluate metastatic disease or local recurrence.

Smooth muscle tumors of the gastrointestinal tract: an analysis of prognostic features in 407 cases

Smooth muscle tumors represent the second most common mural mesenchymal neoplasm in the gastrointestinal tract, but established criteria for prognostic assessment of these tumors are lacking. A large cohort of surgically resected intramural gastrointestinal smooth muscle tumors from 31 institutions was analyzed to identify potential prognostic features. Pathologic features were assessed by expert gastrointestinal and/or soft tissue pathologists at each center. Immunohistochemical confirmation was required. A total of 407 cases from the esophagus (n = 97, 24%), stomach (n = 180, 44%), small bowel (n = 74, 18%), and colorectum (n = 56, 14%) were identified. Patients ranged in age from 19 to 92 years (mean 55 years), with a slight female predominance (57%). Mean tumor size was 5.4 cm, with the largest tumor measuring 29 cm. Disease progression following surgery, defined as local recurrence, metastasis, or disease-related death, occurred in 56 patients (14%). Colorectal tumors were most likely to progress, followed by small bowel and gastric tumors. None of the esophageal tumors in this series progressed. Receiver operator characteristic analysis identified optimal cutoffs of 9.8 cm and 3 mitoses/5 mm² for discriminating between progressive and non-progressive tumors. Histologic features strongly associated with progression by univariate analysis included moderate-to-severe atypia, high cellularity, abnormal differentiation (defined as differentiation not closely resembling that of normal smooth muscle), tumor necrosis, mucosal ulceration, lamina propria involvement, and serosal involvement (P < 0.0001 for all features). Age, sex, and margin status were not significantly associated with progression (P = 0.23, 0.82, and 0.07, respectively). A risk assessment table was created based on tumor site, size, and mitotic count, and Kaplan-Meier plots of progression-free survival for each subgroup revealed progression-based tiers. Based on our findings, it appears that nonesophageal gastrointestinal smooth muscle tumors measuring >10 cm and/or showing ≥3 mitoses/5 mm² may behave aggressively, and therefore close clinical follow-up is recommended in these cases.

Mesenteric Lymph Node Recurrence of a Primary Colorectal Leiomyosarcoma

Primary colorectal leiomyosarcoma is an excessively rare entity. It is associated with an aggressive behavior and typically favor hematogenous spread. The current standard of care is surgical resection. A 49-year-old patient presented with a 2-month history of fever. A PET-scan revealed a hypermetabolic mass in the transverse colon, and colonoscopy confirmed a tumor. A right hemicolectomy was performed. Histopathological diagnosis was of a leiomyosarcoma. Fourteen months after the surgery, a follow-up abdominal scan revealed a 2 cm mesenteric lymph node that was hypermetabolic on PET-scan. The mesenteric lymph node was resected and histopathology confirmed a leiomyosarcoma metastasis. This case opens the controversy on the management of rare lymph node recurrences in colorectal leiomyosarcoma.

Huge Gastrointestinal Stromal Tumor of the Jejunum Presenting as Bowel Obstruction: A Rare Presentation

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract arising from interstitial Cajal cells. A 54-year-old male patient without any comorbidities presented to the emergency department with complaints of abdominal distension, inability to pass flatus, and no motion for the past 2 days. Abdominal X-ray showed multiple air-fluid levels suggesting bowel obstruction. The patient was managed conservatively at first. Later, ultrasonography and contrast-enhanced computed tomography (CECT) of the abdomen were done, which revealed a mass lesion arising from the jejunum suggestive of GIST. The patient was taken up for exploratory laparotomy, and a tumor was found in the proximal jejunum around 10 cm from the duodenojejunal junction and encompassing the hepatic flexure of the transverse colon, with the omentum found adhered to the anterior surface of the lesion and distended proximal bowel loops. There was no evidence of mesenteric lymphadenopathy. The mass was resected along with the jejunal loop and the hepatic flexure of the colon, followed by end-to-end jejunojejunal anastomosis and end-to-end colocolic anastomosis. The patient's postoperative stay was uneventful. Imatinib therapy was started following histopathological confirmation and continued. The patient was followed up for 1 year postoperatively with CECT of the abdomen every 6 months, with no evidence of recurrence or any gastro-intestinal symptoms.

Gastrointestinal Stromal Tumors of Small Intestine

Gastrointestinal stromal tumor (GIST) is defined as mesenchymal tumors of the gastrointestinal tract expressing proto-oncogene protein CD117. They are the most common sarcomatous tumors of the gastrointestinal tract. GISTs are presumed to arise from interstitial cells of Cajal or gastrointestinal pacemaker cells which control gut motility. They have unpredictable biological behavior. Prognosis is dependent on tumor size as well as mitotic count. Radical surgical excision is the treatment of choice. They rarely metastasize to lymph nodes. Imatinib therapy is used as an adjuvant therapy. The follow-up of patients postsurgery is not standardized.

Clinical Diagnosis of Gastrointestinal Stromal Tumor (GIST): From the Molecular Genetic Point of View

Gastrointestinal stromal tumors (GISTs) originating from the interstitial cells of Cajal are mesenchymal tumors of the gastrointestinal tract and have been found to harbor c-KIT mutations and KIT (CD117) expression since 1998. Later, PDGFRA mutations, SDH alterations, and other drive mutations were identified in GISTs. In addition, more and more protein markers such as DOG1, PKCθ were found to be expressed in GISTs which might help clinicians diagnose CD117-negative GISTs. Therefore, we plan to comprehensively review the molecular markers and genetics of GISTs and provide clinicians useful information in diagnostic and therapeutic strategies of GISTs. Twenty years after the discovery of KIT in GISTs, the diagnosis of GISTs became much more accurate by using immunohistochemical (IHC) panel (CD117/DOG1) and molecular analysis (KIT/PDGFRA), both of which constitute the gold standard of diagnosis in GISTs. The accurately molecular diagnosis of GISTs guides clinicians to precision medicine and provides optimal treatment for the patients with GISTs. Successful treatment in GISTs prolongs the survival of GIST patients and causes GISTs to become a chronic disease. In the future, the development of effective treatment for GISTs resistant to imatinib/sunitinib/regorafenib and KIT/PDGFRA-WT GISTs will be the challenge for GISTs.

Laparoscopic surgery to treat leiomyosarcomas of the sigmoid colon:a case report and literature review

Background

Leiomyosarcomas (LMSs) of the colon are extremely rare and highly aggressive. Although treatment of gastrointestinal LMS is not standardized, surgical resection is generally performed. The fact that the tumors are usually large at the time of diagnosis may explain why no report on laparoscopic resection of a colonic LMS has appeared.

Case presentation

A 46-year-old male presented with hematochezia 1 month in duration. Abdominal examination including palpation was normal. The levels of several blood tumor markers were normal. Colonoscopy revealed a polypoid lesion approximately 30 mm in diameter in the sigmoid colon 30 cm from the anal verge. Contrast-enhanced computed tomography revealed that the tumor was 28 mm in diameter, and that no lymph node or distant metastasis was apparent. Histopathological examination of a biopsy specimen revealed spindle-shaped cells exhibiting significant nuclear atypia and a trabecular proliferation pattern upon hematoxylin-eosin staining. Immunohistochemically, the sample was positive for SMA and desmin, and negative for c-kit, DOG-1, CD34, and S-100. Furthermore, the Ki-67 index was > 50%. We thus diagnosed a leiomyosarcoma of the sigmoid colon without any metastasis. We performed laparoscopic sigmoid colectomy and regional lymphadenectomy using five trocars. After complete curative resection, a colorectal end-to-end anastomosis was created employing the double-stapling technique. All surgical margins were negative, and no lymph node metastasis was observed. The postoperative course was uneventful, and the patient was discharged 9 days after operation. No recurrence was noted to 1 year after surgery.

Conclusions

We report the first case of a colonic LMS treated via laparoscopic surgery. Although further work is necessary to assess prognosis and to develop the treatment further, laparoscopic surgery to treat small colonic LMSs may be feasible, being both minimally invasive and curative.

Association of ki67 Index with Recurrence in Gastrointestinal Stromal Tumors

PURPOSE

Gastrointestinal stromal tumors (GIST) have the potential to recur and metastasize. Several prognostic schemes have been developed but none are precise enough and most times the pathologist faces a small biopsy where it is not possible to evaluate the mitotic count. Our aim was to determine the influence of ki67 index and other clinicopathologic characteristics in the recurrence of GIST.

METHODS

Forty-three consecutive cases of GIST were studied. The cases presented with non-metastatic disease. We compared the clinicopathologic features of cases with recurrence against those with non-recurrence. The ki67 index was determined by square-millimeters.

RESULTS

The median age was 55 years (IQR 45-63), the most frequent site of involvement was the stomach with 21 (48.8%) cases, and the median of tumor diameter was 10 cm (IQR 5.5-17.5). Twenty-six (60.5%) cases were spindle cell, 13 (30.2%) were mixed, and 4 (9.3%) were epithelioid. The median mitosis count for 50 high power fields was 4 (IQR 0-16), while per square millimeter it was 1 (IQR 0-5, range 0-32). The median of the ki67 proliferation index was 5% (IQR 1-20). During the period of study, 11 (25.6%) patients recurred. The only significant differences between patients with GIST with recurrence and without recurrence were the sex and tumor size.

CONCLUSION

We did not find an association of the ki67 index with recurrence. The factors associated with recurrence were a high tumor size (> 10 cm) and male sex.

Malignant peripheral nerve sheath tumor of the transverse colon with peritoneal metastasis: a case report

Background

Malignant peripheral nerve sheath tumors are malignant tumors arising from a peripheral nerve or displaying nerve sheath differentiation. Gastrointestinal malignant peripheral nerve sheath tumors are rare and malignant peripheral nerve sheath tumor of the colon is even rarer. To date, only five cases have been reported as malignant peripheral nerve sheath tumor arising in the colon. This is probably the first case report of malignant peripheral nerve sheath tumor of the transverse colon associated with peritoneal metastasis.

Case presentation

A 25-year-old Indian man presented with a large abdominal mass. A computed tomography scan revealed a large 18 cm-sized mass in his transverse colon, suggestive of gastrointestinal stromal tumor. A wide local excision was performed. Histopathology showed sheets and fascicles of elongated to spindle-shaped tumor cells showing a moderate degree of pleomorphism and atypia. Based on morphology and immunohistochemistry, a final diagnosis of malignant peripheral nerve sheath tumor of the transverse colon was given. A peritoneal metastatic tumor deposit was identified grossly and confirmed on histopathology.

Conclusion

This is a rare case report discussing the detailed diagnostic approach along with an extensive review of the literature for malignant peripheral nerve sheath tumor arising in the colon.

Electronic supplementary material

The online version of this article (10.1186/s13256-018-1896-4) contains supplementary material, which is available to authorized users.

Gastrointestinal Stromal Tumors: Clinical Symptoms, Location, Metastasis Formation, and Associated Malignancies in a Single Center Retrospective Study

BACKGROUND AND AIMS

Gastrointestinal stromal tumors (GISTs) are rare malignancies but the most common mesenchymal tumors of the digestive tract. Recent advances in diagnostic imaging and an increasing incidence will confront us more frequently with stromal tumors. This single center study aimed to characterize GIST patients in terms of tumor location, clinical presentation, metastasis formation, as well as associated secondary malignancies.

METHODS

In a retrospective study, 104 patients with a histologically confirmed diagnosis of GIST, collected between 1993 and 2011, were characterized for several clinical features.

RESULTS

The most common GIST location was the stomach (67.6%) followed by the small intestine (16.2%). Gastrointestinal bleeding (55.8%) and abdominal pain (38.5%) were the most frequently reported symptoms whereas about one-third of patients remained clinically asymptomatic (31.6%); 14.4% of patients had either synchronous or metachronous metastases and there was a significant prevalence also in the low risk group. The proportion of secondary malignant associated neoplasms was 31% in our GIST cohort, among which gastrointestinal, genitourinary tumors, and breast cancer were the most prevalent.

CONCLUSION

There was a considerable risk for metastasis formation and the development of secondary neoplasias that should encourage discussion about the appropriate surveillance strategy after surgery for GIST.

Nongastrointestinal Stromal Tumor Spindle Cell Sarcomas of the Colon or Rectum

Because of the low incidence of nongastrointestinal stromal tumor (non-GIST) spindle cell sarcomas of the colon or rectum, the clinical behavior and ideal surgical treatment of these tumors and patient outcomes are poorly defined. The purpose of this study was to characterize these tumors and to determine the best surgical approach. We identified 1056 patients with non-GIST spindle cell sarcomas of the colon or rectum (1998–2010) in the National Cancer Database and collected data for each patient that included patient and tumor characteristics, tumor site (colon vs rectum), surgery type, and outcomes. The median overall survival was significantly longer in patients with rectal tumors than in those with colon tumors ( P < 0.01). Patients with colon tumors who underwent anatomic surgical resection showed a trend toward longer median survival than those with no surgical treatment [hazard ratio (HR), 1.94; P = 0.09] or who underwent local excision (HR, 1.74; P = 0.09). Patients with rectal tumors did not benefit from anatomic surgical resection, but there was a trend favoring local excision (HR, 0.55; P = 0.06). Local sphincter-sparing procedures should be considered for rectal non-GIST tumors whenever technically feasible.

Lack of Prognostic Significance of Connexin-43 Labeling in a Series of 46 Gastrointestinal Stromal Tumors

Background

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors with variable malignant potential. Connexin-43 (C×43) is the commonest gap-junction protein and has been frequently investigated in oncology. Our aim was to establish the immunohistochemical expression of C×43 in relation to GIST location, size, Ki67 index, tumor grade and follow-up.

Materials and methods

The study included postoperative samples of 46 patients treated for GIST in the 1999–2010 time frame. Complete clinical workup was available for 38 patients (82.6%); total surgical resection was carried out in 32 (84.2%) patients, while 13 (34.2%) patients underwent chemotherapy. Median follow-up was 40.7 months (range, 1-134).

Results

The calculated incidence of GIST in our setting was 11.5 per million. C×43 was expressed in 43/46 (93.5%) GIST cases, with a significant difference between stomach- and small intestine-derived tumors (p=0.006). Ki67 was 10% on average (range, 1–22) and was not correlated with tumor location (p=0.194). C×43 did not show significance with regard to tumor size (p=0.264) or higher tumor grade (p=0.658), as opposed to Ki67, which significantly correlated with both (p=0.0048 and p<0.001, respectively). C×43 and Ki67 were not significantly correlated (p=0.708). Ki67 correlated with time to recurrence (p=0.022). Ki67 >11% was taken as the indication to start imatinib chemotherapy (sensitivity 61.5%, specificity 92.0%, p=0.022). Ten (66.7%) of 15 patients with long-term (>5 years) follow-up were in remission.

Conclusion

C×43 was frequently expressed in GISTs regardless of tumor site. However, no significant relationships to histopathological parameters suggestive for prognosis were found. Further investigations might clarify the roles of C×43 in GIST oncogenesis.

Neural and neurogenic tumours of the gastroenteropancreaticobiliary tract

Neural lesions occur uncommonly in the gastroenteropancreaticobiliary tract. However, due to the growing number of screening colonoscopy procedures, polypoid neural lesions of the colon are being recognised increasingly and range from benign tumours to high-grade malignant neoplasms. Morphological variability of neural tumours can be wide, although some entities share pathological features, and, as such, these lesions can be diagnostically challenging. We review the spectrum of pathology of neural tumours in the gastroenteropancreaticobiliary tract, with the goal of providing a practical approach for practising surgical pathologists.

Molecularly Targeted Therapy and Radiotherapy in the Management of Localized Gastrointestinal Stromal Tumor (GIST) of the Rectum: A Case Report

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. The main treatment for localized gastrointestinal stromal tumors is surgical resection. These tumors respond poorly to conventional cytotoxic chemotherapy agents and to radiotherapy. Imatinib mesylate, a small-molecule kinase inhibitor, has proved useful in the treatment of recurrent or metastatic GISTs and is now being tested in the adjuvant and neoadjuvant setting. The role of radiotherapy in the management of patients with GIST is currently restricted to symptomatic palliation.

We present the case of a 54-year-old man affected by rectal GIST extending to the anal canal, with constipation, hematochezia, and anal pain. He received imatinib, 400 mg orally per day, for a week before and during radiation therapy. Irradiation was delivered to the gross tumor volume by 3D conformal therapy. The planned total dose was 50.4 Gy in fractions of 1.8 Gy daily. We observed a partial clinical response 3 weeks after the end of combination treatment. The patient then underwent a sphincter-saving surgical procedure. There was no perioperative morbidity and a complete pathological response was obtained.

At the present time, the role of radiotherapy in the management of patients with GIST is restricted to symptomatic palliation. The introduction of molecularly targeted therapy combined with radiation therapy could improve the outcomes for patients diagnosed with GIST.

Rectal gastrointestinal stromal tumour: What do we know in 2017? A systematic review protocol

Introduction

Gastrointestinal stromal tumour is a pathology that originates from the interstitial cells of Cajal and differentiates from other mesenchymal neoplasm by expression of CD117 oncogene on Immunohistochemistry test. Colon and Rectal GISTs constitutes of approximately 5% of all gastrointestinal GISTs. The past decade has witnessed a dramatic change in the treatment of rectal cancer. Preoperative, perioperative and postoperative, management has changed thanks to new chemotherapy regimens and emergence of novel surgical techniques. Our aim is to investigate if same change can be implemented for rectal GISTs management.

Methods and analysis

This protocol is compliant with the Preferred Reporting Items for Systematic Review and Meta-Analysis protocols (PRISMA-P) guidelines. Exclusion and inclusion criteria are outlined within this protocol. Points of interest and objectives are described within this protocol. The search strategy, aims to identify all articles on "Rectal GISTs".

Discussion

The choice of resection type surgery depends upon the location and size of rectal GIST. Neoadjuvant Imatinib therapy yields tumour shrinkage in at least 50% and is associated with a prolonged disease-free survival for intermediate and high-risk patients. This review will also allow a summary clinicopathological features and prognostic factors of rectal GISTs.

Ethics and dissemination

The Centre for Reviews and Dissemination, University of York acknowledged that this systematic review is within the register scope. This review will be published in a peer-reviewed journal and will be presented at various national and international conferences.

Surgical Pathology of Gastrointestinal Stromal Tumors: Practical Implications of Morphologic and Molecular Heterogeneity for Precision Medicine

Gastrointestinal stromal tumor (GIST), the most common mesenchymal neoplasm of the gastrointestinal tract, exhibits diverse histologic and clinical manifestations. With its putative origin in the gastrointestinal pacemaker cell of Cajal, GIST can arise in association with any portion of the tubular gastrointestinal tract. Morphologically, GISTs are classified as spindled or epithelioid, though each of these subtypes encompasses a broad spectrum of microscopic appearances, many of which mimic other histologic entities. Despite this morphologic ambiguity, the diagnosis of GIST is aided in many cases by immunohistochemical detection of KIT (CD117) or DOG1 expression. The natural history of GIST ranges from that of a tumor cured by surgical resection to that of a locally advanced or even widely metastatic, and ultimately fatal, disease. This clinicopathologic heterogeneity is paralleled by an underlying molecular diversity: the majority of GISTs are associated with spontaneous activating mutations in KIT, PDGFRA, or BRAF, while additional subsets are driven by genetic lesions-often inherited-of NF1 or components of the succinate dehydrogenase enzymatic complex. Specific gene mutations correlate with particular anatomic or morphologic characteristics and, in turn, with distinct clinical behaviors. Therefore, prognostication and treatment are increasingly dictated not only by morphologic clues, but also by accompanying molecular genetic features. In this review, we provide a comprehensive description of the heterogenous molecular underpinnings of GIST, including implications for the practicing pathologist with regard to morphologic identification, immunohistochemical diagnosis, and clinical management.

Gastrointestinal stromal tumours of the oesophagus: a clinicopathological and molecular analysis of 27 cases

AIMS

Gastrointestinal stromal tumours (GISTs) may arise anywhere in the gastrointestinal tract, but are rare in the oesophagus. We describe the clinical, pathological and molecular characteristics of 27 primary oesophageal GISTs, the largest series to date.

METHODS AND RESULTS

DNA was extracted and exons 9, 11, 13 and 17 of KIT, exons 12, 14 and 18 of PDGFRA and exon 15 of BRAF were amplified and sequenced. Oesophageal GISTs occurred in 14 men and 13 women aged between 22 and 80 years (mean: 56 years). All 27 cases were immunohistochemically positive for KIT, and 92 and 47% co-expressed CD34 or smooth muscle actin, respectively. Fifteen (71% of analysed cases) harboured KIT exon 11 mutations and one case each had a mutation in KIT exon 13 (K642E) or BRAF exon 15 (V600E). Long-term follow-up data (median, 96.5 months) were obtained for 20 cases; two patients had metastases at presentation and seven had developed local recurrence and/or metastasis after surgery. A large tumour size (≥ 10 cm), high mitotic rate (> 5/5 mm² ), presence of a deletion mutation in KIT exon 11 involving codons 557-558 and a positive microscopic margin were associated with recurrence and metastasis. The KIT mutations identified in oesophageal GISTs are similar to those observed in gastric GISTs.

CONCLUSIONS

Complete surgical resection with clear margins is recommended, if technically feasible, and genotyping can help to improve diagnosis and further patient management in oesophageal GIST.

Giant leiomyosarcoma of the rectum with lymph node metastasis: A case report and review of the literature

INTRODUCTION

Leiomyosarcoma of the gastrointestinal tract is very rare, with a reported frequency of less than 0.1% of all malignancies of the colorectum. It is important to diagnose leiomyosarcoma definitively by immunohistochemical profiling of smooth muscle actin, desmin, and CD34. True leiomyosarcoma of the colorectum diagnosed by immunnohistochemical profiling is extremely rare that only 13 reports have been published in reviews of resected gastrointestinal mesenchymal tumors after 1998. In addition, lymph node involvement is rare in patients with leiomyosarcoma. Herein we report an aggressive case of LMS in a rectosigmoid lesion with lymph node metastasis.

CASE PRESENTATION

A 76-year-old woman visited our hospital complaining of intermittent anal bleeding that had lasted 5 months. Image studies aiming at examining the cause of her anal bleeding revealed a tumor located between the right ovary, uterus, and the rectosigmoid. Histopathology of biopsied materials from the colonoscopy suggested a malignant tumor of mesenchymal origin. Surgical resection was performed with curative intent. The tumor was diagnosed as leiomyosarcoma by pathological examination. Moreover, one of the 31 regional lymph nodes retrieved was metastasized by leiomyosarcoma. Eight months later, follow-up CT scans revealed multiple recurrent lesions in the liver and peritoneum. Despite systematic chemotherapy, she deceased 12 months after the surgery.

CONCLUSION

It is crucial to diagnose leioyosarcoma precisely based on immunohistochemistry, and thereby distinguish it from GIST. Although lymph node metastasis is rare, lymphadenectomy appears to be important for high-risk LMSs to perform R0 resection. Further investigation on leiomyosarcoma cases so far is required to establish standard treatment strategies.

Synchronous coexistence of liver metastases from cecal leiomyosarcoma and rectal adenocarcinoma: A case report

Multiple liver tumors represent a challenging condition for abdominal surgeons both in the selection of technique and the rarity of diagnosis. There are no case reports on co-existence of liver metastases from both intestinal leiomyosarcoma and adenocarcinoma. The patient described in this report successfully underwent resection of both primary lesions and liver metastases in combination with chemotherapy. As for the leiomyosarcoma, the primary cecal lesion was revealed more than three years after the patient's first visit. Peritoneal, lymph-node, and lung recurrences were observed afterward, and thus surgeries on those regions were performed. Pathologically, the peritoneal and lung recurrences comprised leiomyosarcoma and the lymph-node recurrence was diagnosed as adenocarcinoma. Despite newly discovered multiple lung recurrences and regional lymph-node metastases, the patient lived a normal life for 73 mo after the initial operation based on multidisciplinary therapy. He ultimately died of liver failure due to invasive lymph-node recurrence from the rectal adenocarcinoma, in addition to multiple lung recurrences from the leiomyosarcoma. Hepatic recurrence did not occur in this patient's case, which appears to be one reason for his long-term survival.

CT Features of Colorectal Schwannomas: Differentiation from Gastrointestinal Stromal Tumors

Purpose

To find differential CT features of colorectal schwannomas from gastrointestinal stromal tumors (GISTs).

Materials and Methods

CT features of 13 pathologically proven colorectal schwannomas and 21 GISTs were retrospectively reviewed. The following CT items were analyzed: size, longitudinal and transverse location, shape, margin, homogeneity, necrosis, surface ulceration, calcification, degree of attenuation, the presence of enlarged lymph node (LN), and metastasis. Among the features, significant variables were evaluated using univariate statistical tests. The optimal cut-off point of tumor size was obtained by ROC analysis. Binary logistic regression analysis was used to find the most independent CT variables.

Results

Small size, non-rectum location, smooth margin, homogeneous high attenuation without necrosis, and the presence of enlarged LNs were found to be significant variables to differentiate schwannomas from GISTs (P<0.05). The optimized cut-off point for tumor size in distinguishing GISTs from schwannomas was 3.9 cm (AUC = 0.808, sensitivity = 66.7%, specificity = 92.3%, P<0.0001). Binary regression analysis revealed that only non-rectum location remained independent predictor for schwannomas differentiated from GISTs (odds ratio = 31.667, P = 0.001).

Conclusion

Colorectal schwannomas usually located in non-rectum and appear as small subepithelial nodules showing homogeneous high attenuation and smooth margin. Schwannomas exclusively accompany with enlarged LNs.

Genetic variations in the TERT and CLPTM1L gene region and gastrointestinal stromal tumors risk

Recent studies have suggested polymorphisms in the TERT and CLPTM1L region are associated with carcinogenesis of many distinct cancer types, including gastrointestinal cancers. However, the contribution of polymorphisms in the TERT and CLPTM1L gene region to gastrointestinal stromal tumors (GISTs) risk is still unknown. We tested the six tagSNPs on TERT and CLPTM1L region with GIST risk, using a population-based, two-stage, case-control study in 2,000 subjects. Functional validation was conducted to validate our findings of TERT rs2736098 and explore its influence on relative telomere length (RTL) in GIST cells. It showed that variant rs2736098 was significantly associated with increased risk of GIST (per allele OR = 1.29, 95% CI: 1.14–1.47, P = 7.03 × 10⁻⁵). The difference remain significant after Bonferroni correction (P = 7.03 × 10⁻⁵ * 6 = 4.2 × 10⁻⁴). Real-time PCR showed carriers of genotype CC have the longest RTL, following by carriers of genotype CT, while carriers of genotype TT have the shortest RTL in GIST tissues (P < 0.001). Our data provide evidence to implicate TERT rs2736098 polymorphism as a novel susceptibility factor for GIST risk.

Clinicopathological features and prognosis of colonic gastrointestinal stromal tumors: evaluation of a pooled case series

Background

Due to the extremely rare incidence, data about colonic GISTs are limited. Therefore, aim of the present study was to explore clinicopathological characteristics and prognosis of colonic GISTs.

Patients and Methods

Colonic GISTs cases were obtained from our center and from case report and clinical studies extracted from MEDLINE. Clinicopathological features and survivals were analyzed.

Results

There were 79 colonic GISTs patients with a female predominance. The median age was 66 years (range 0.17-84). The median tumor size was 5.8 cm (range 0.5-29). The most common location was sigmoid colon (45.8%), followed by transverse colon (19.5%). The majority of colonic GISTs were high risk (70.8%). Mitotic index was correlated with gender (P = 0.002) and tumor size (P = 0.005), and tumor location was correlated with age (P = 0.017). The five year DFS and DSS were 57.4% and 61.6%, respectively. Mitotic index and NIH risk classification were associated with prognosis of colonic GISTs. However, mitotic index was the only independent risk factor. The distribution of tumor size and NIH risk classification were significantly different between colonic and gastric GISTs (both P = 0.000). The DFS and DSS of colonic GISTs were significantly lower than that of gastric GISTs (P = 0.012 and P = 0.002, respectively).

Conclusions

The most common location for colonic GISTs was sigmoid colon. Most tumors were high risk. Mitotic index was the only independent risk factor for prognosis of colonic GISTs. Colonic GISTs differ significantly from gastric GISTs in respect to clinicopathological features. The prognosis of colonic GISTs was worse than that of gastric GISTs.

Gastrointestinal (GI) leiomyosarcoma (LMS) case series and review on diagnosis, management, and prognosis

This review of 76 gastrointestinal (GI) leiomyosarcoma (LMS) cases that include 11 cases from the American University of Beirut Medical Center represents, to our knowledge, the largest number of combined GI LMS cases reported. The age range of GI LMS is variable, and the presentation is non-specific, making pathological diagnosis essential. LMSs usually lack CD117 and CD 34 mutations and are usually positive for smooth muscle cell markers. The review highlights surgery as the mainstay of treatment with negative margins attained most of the times. Adjuvant chemotherapy is used in around 7-27 % of the cases mainly for small intestinal and colorectal LMS. The relatively small number of patients is a limitation on outcome analysis. However, LMS has a risk of recurrence reaching 39-80 % and secondary metastasis reaching 55-71 % in small intestinal and colorectal cases. In light of the high frequency of recurrence and metastasis, enrolling patients in clinical randomized trials to investigate the role of chemotherapy, radiation therapy, and targeted therapy is required for better control of this rare aggressive GI tumor.

A Rare Case of Colonic Leiomyosarcoma in Association with Ulcerative Colitis

Ulcerative colitis (UC) is known to be associated with an increased risk of colorectal cancer. However, the occurrence of non-epithelial malignancies is uncommon. An elevated lesion in the descending colon was found in a 51-year-old woman with a 30-year history of UC. Despite tumor progression, repeated biopsies showed no cancerous findings. Because the lesion was highly suspected to be a malignant tumor, a partial colectomy was performed. The pathological diagnosis was leiomyosarcoma. Leiomyosarcoma of the gastrointestinal tract is rare, and this is only the third known case reported in patients with UC.

Pathologic Features of Primary Colon, Rectal, and Anal Malignancies

In the United States, colorectal cancer is the third most commonly diagnosed cancer in both men and women, as well as the third leading cause of cancer deaths (Colorectal cancer facts & figures 2014–2016, 2014 [2]). Worldwide, colorectal cancer is the fourth leading cause of death and causes almost 700,000 deaths each year (Cancer: fact sheet No. 297, 2015 [55]). This chapter discusses the clinical and pathologic features of the spectrum of epithelial, hematolymphoid, and mesenchymal malignant tumors of the colon, rectum, appendix, and anus.

Primary leiomyosarcoma of the colon

Primary leiomyosarcomas of the gastrointestinal (GI) tract are extremely rare and highly aggressive neoplasms, and only a small number of true cases have been reported since the concept of GI stromal tumors was established. Here, we report a case of a primary leiomyosarcoma of the transverse colon. A 46-year-old Japanese male with a large mass in the right upper abdomen was admitted to our hospital. Computed tomography and magnetic resonance imaging revealed long segments of wall thickening of the transverse colon with large consecutive tumors measuring 12 cm in diameter. A projecting irregular mass with marked mucosal necrosis was found on colonoscopy. Pathological examination revealed a spindle cell tumor growing circumferentially and transmurally to replace the muscularis propria in the transverse colon. The spindle cells were positive for smooth muscle actin, and negative for KIT, CD34, DOG-1, and S-100 protein. The patient has shown repeat recurrence in spite of sufficient surgical excision being promptly performed.

Gastrointestinal stromal tumor - an evolving concept

Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal tract. The discovery that these tumors, formerly thought of smooth muscle origin, are indeed better characterized by specific activating mutation in genes coding for the receptor tyrosine kinases (RTKs) CKIT and PDGFRA and that these mutations are strongly predictive for the response to targeted therapy with RTK inhibitors has made GISTs the typical example of the integration of basic molecular knowledge in the daily clinical activity. The information on the mutational status of these tumors is essential to predict (and subsequently to plan) the therapy. As resistant cases are frequently wild type, other possible oncogenic events, defining other "entities," have been discovered (e.g., succinil dehydrogenase mutation/dysregulation, insuline growth factor expression, and mutations in the RAS-RAF-MAPK pathway). The classification of disease must nowadays rely on the integration of the clinico-morphological characteristics with the molecular data.

Gastro-intestinal stromal tumor (GIST) complicating a colonic interposition: a novel case report

Background

Gastrointestinal stromal tumor (GIST) is a rare tumor comprising 0.1-0.3% of all gastrointestinal (GI) malignancies. Stomach followed by small intestine is the most common sites of involvement, implicated in 95% of the cases. We present a case of GIST complicating a colonic interposition. To the best of the author's knowledge, this is the first reported case of GIST complicating a colonic interposition.

Case presentation

A 47 year old African American male presented to the emergency department with intermittent, severe chest pain. Past medical history was significant for alkali (NaOH) ingestion during 1980 for which esophageal resection and a colonic pull-through was performed. A CXR revealed a widened mediastinum and CT scan chest revealed showed a large (11.4 × 8.3 × 12.1 cm) vascular mediastinal mass. At endoscopy, a large, ulcerated, cratered and friable mass was found at 29cm extending to 36cm at which point the lower anastomosis of the colonic pull through was present. Multiple endoscopic biopsies were obtained which showed that the tumor was immunoreactive with CD117, CD34 and DOG1 while markers of carcinoma, melanoma and lymphoma were negative. In light of the pathology report, the immunohistochemistry and the CT scans, the tumor was classified as a stage 4 GIST of colonic interposition.

Conclusions

GIST can complicate unusual locations such as colonic interposition and should be kept in the differential diagnosis of such unusual presentations.

Beyond the GIST: mesenchymal tumors of the stomach

Intramural gastric masses arise in the wall of the stomach (generally within the submucosa or muscularis propria), often with intact overlying mucosa. These tumors are typically mesenchymal in origin and have overlapping radiologic appearances. A combination of features such as location, attenuation, enhancement, and growth pattern may suggest one diagnosis over another. Gastrointestinal stromal tumors (GISTs) account for the majority of intramural tumors and can vary widely in appearance, from small intraluminal lesions to exophytic masses that protrude into the peritoneal cavity, commonly with areas of hemorrhage or necrosis. A well-circumscribed mass measuring -70 to -120 HU is a lipoma. Leiomyomas usually manifest as low-attenuation masses at the gastric cardia. Homogeneous attenuation is a noteworthy characteristic of schwannomas, particularly for larger lesions that might otherwise be mistaken for GISTs. A hypervascular mass in the antrum is a common manifestation of glomus tumors. Hemangiomas are also hypervascular but often manifest in childhood. Inflammatory fibroid polyps usually arise as a polypoid mass in the antrum. Inflammatory myofibroblastic tumors are infiltrative neoplasms with a propensity for local recurrence. Plexiform fibromyxomas are rare, usually antral tumors. Carcinoid tumors are epithelial in origin, but often submucosal in location, and therefore should be distinguished from other intramural lesions. Multiple carcinoid tumors are associated with hypergastrinemia, either in the setting of chronic atrophic gastritis or Zollinger-Ellison syndrome. Sporadic solitary carcinoid tumors not associated with hypergastrinemia have a higher rate of metastasis. Histopathologic analysis, including immunohistochemistry, is usually required for diagnosis of intramural masses.

The diagnostic importance of matrix metalloproteinase-7 and nestin in gastrointestinal stromal tumors

BACKGROUND

The importance of the matrix metalloproteinase-7 (MMP-7) and nestin immunomarkers, C-kit proto-oncogene (CD117), and the efficiency of the Ki-67 proliferation index for gastrointestinal stromal tumors were evaluated.

MATERIAL AND METHODS

This study was conducted by examining the microscope slides of 72 patients with gastrointestinal stromal tumors that were sent to the pathology laboratory between 2007 and 2012. Immunohistochemical staining for CD117, MMP-7, nestin, and marker of proliferation Ki-67 was performed. The correlations between the positive results for Ki-67, CD117, MMP-7, and nestin were evaluated relative to the tumor characteristics of size, localization, grade, cellular type, cellularity, cytology type, growth pattern, ulceration, necrosis, hemorrhage, invasion depth, and lymph node metastasis.

RESULTS

The tumor was localized in the stomach in 42 of the patients, the intestines in 19, the colon in 7, and the rectum in 4. Comparisons among the groups showed that MMP-7 was correlated with the tumor grade (p<0.001), cellularity (p<0.009), cytologic atypia (p<0.001), ulceration (p=0.002), necrosis (p<0.001), and tumor size (p=0.001). Nestin was correlated with the tumor grade (p=0.013), and tumor size (p=0.024). Correlations among CD117, MMP-7, nestin, and Ki-67 were examined. Nestin and Ki-67 were both significantly correlated with CD117 and MMP-7 [(r=0.279, p=0.018), (r=0.322, p=0.006), (r=0.386, p=0.001), (r=0.386, p=0.002)], respectively.

CONCLUSIONS

MMP-7 and nestin may be beneficial as markers, given their sensitivity to gastrointestinal stromal tumors.

Smooth muscle tumors of soft tissue and non-uterine viscera: biology and prognosis

Smooth muscle tumors are here considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas. Soft tissue smooth muscle tumors with both atypia and mitotic activity are generally diagnosed leiomyosarcomas acknowledging potential for metastasis. However, lesions exist that cannot be comfortably placed in either category, and in such cases the designation 'smooth muscle tumor of uncertain biologic potential' is appropriate. The use of this category is often necessary with limited sampling, such as needle core biopsies. Benign smooth muscle tumors include smooth muscle hamartoma and angioleiomyoma. A specific category of leiomyomas are estrogen-receptor positive ones in women. These are similar to uterine leiomyomas and can occur anywhere in the abdomen and abdominal wall. Leiomyosarcomas can occur at any site, although are more frequent in the retroperitoneum and proximal extremities. They are recognized by likeness to smooth muscle cells but can undergo pleomorphic evolution ('dedifferentiation'). Presence of smooth muscle actin is nearly uniform and desmin-positivity usual. This and the lack of KIT expression separate leiomyosarcoma from GIST, an important problem in abdominal soft tissues. EBV-associated smooth muscle tumors are a specific subcategory occurring in AIDS or post-transplant patients. These tumors can have incomplete smooth muscle differentiation but show nuclear EBER as a diagnostic feature. In contrast to many other soft tissue tumors, genetics of smooth muscle tumors are poorly understood and such diagnostic testing is not yet generally applicable in this histogenetic group. Leiomyosarcomas are known to be genetically complex, often showing 'chaotic' karyotypes including aneuploidy or polyploidy, and no recurrent tumor-specific translocations have been detected.

Perforation as a rare presentation of gastric gastrointestinal stromal tumours: a case report and review of the literature

INTRODUCTION

Gastrointestinal stromal tumours (GISTs) are the most common connective tissue neoplasms of the gastrointestinal tract, the most common clinical presentation of which is with abdominal pain or gastrointestinal bleeding.

METHODS

We describe a case of a perforated gastric GIST as well as reviewing the relevant published literature.

RESULTS

A 51-year-old woman presented to the acute assessment unit with a 1-day history of severe epigastric pain on a background of longstanding reflux symptoms. Radiological investigation demonstrated a perforated mass in the gastric antrum and the patient subsequently underwent an emergency distal gastrectomy. She recovered well postoperatively and was discharged home. Her condition remains stable six months following surgery. Histological analysis revealed the perforated lesion to be a GIST. A PubMed search suggests that this is the first English report to describe a perforated gastric GIST. Six further published reports (written in English or with an English abstract) describing the presentation of small bowel GISTs with perforation are reviewed.

CONCLUSIONS

We present the first English report of a perforated gastric GIST. More common presentations include abdominal pain and gastrointestinal bleeding. Although rare, GISTs should be considered in the differential diagnoses of perforated gastrointestinal masses.

Low ING4 protein expression detected by paraffin-section immunohistochemistry is associated with poor prognosis in untreated patients with gastrointestinal stromal tumors

BACKGROUND

Inhibitor of growth 4 (ING4) has deserved attention as a tumor suppressor gene in many malignant tumors. In our study, we investigated ING4 immunoexpression in gastrointestinal stromal tumors (GISTs) and its prognostic value.

METHOD

The expression of ING4 and Ki67 was investigated in 41 samples of various risk gastrointestinal stromal tumors by immunohistochemical technique. The associations of ING4 expression and clinicopathological parameters, and prognosis of the patients, were analyzed by multivariate Cox regression analysis.

RESULTS

ING4 expression showed a decreased trend from lower-risk to high-risk gastrointestinal stromal tumors, and an opposite trend for Ki67 expression. In lower-risk tumors, it was found the expression level of ING4 was 78.95 % ± 27.90 % and that of Ki67 was 4.42 % ± 3.75 %. However, in high-risk tumors, the expression level of ING4 was 9.23 % ± 7.66 % and that of Ki67 was 18.50 % ± 9.09 %. There was a strongly negative correlation between the expression levels of ING4 and Ki67. A significant difference was observed in the expression of ING4 between invasion and non-invasion (p < 0.001). The expression of ING4 was markedly correlated with tumor size (p < 0.001), mitotic index (p < 0.001), tumor necrosis (p = 0.021), invasion (p < 0.001), recurrence and metastasis (p = 0.021), and mortality (p < 0.001).

CONCLUSION

The low expression level of ING4 protein was correlated with high-risk GISTs. ING4 might be involved in the progression of GISTs and inhibit its invasion. ING4 might be one of the prognostic indicators in GISTs.