GIST: an update

Huge mesenteric fibromatosis presenting with intestinal perforation and acute diffuse peritonitis: a case report

Mesenteric fibromatosis is a locally invasive myofibroblastic proliferation and rarely metastasize to other organs. Hollow organ perforation and acute diffuse peritonitis caused by mesenteric fibromatosis rarely occurred. Here we report a case of huge mesenteric fibromatosis who complained a paroxysmal epigastric pain, and CT scan showed a huge mass, pneumoperitoneum and ascites. An urgent laparotomy showed an intro-abdominal mass and perforation locating at the jejunum. Postoperative histology confirmed it to be mesenteric fibromatosis. With one-year follow-up, the patient had no recurrence. We wish to share our treating experience of this interesting case because it did not belong to a typical type but presenting with acute diffuse peritonitis, and total resection and R0 margin is a key to treat acute case. This atypical one has not been reported in the literature till now.

Primary Prostatic Extra-Gastrointestinal Stromal Tumor Treated with Imatinib Mesylate as Neoadjuvant and Adjuvant Therapy: A Case Report and Literature Review

The current study presents a case of primary prostatic extra-gastrointestinal stromal tumor (EGIST) in a 43-year-old man who suffered acute urinary retention. The serum level of prostate-specific antigen was normal. Imaging examinations demonstrated a diffusely enlarged prostate compressing the rectum without evidence of metastasis. After excluding the possibility of secondary involvement by a rectal GIST, the pathologic diagnosis of primary prostatic EGIST was established based on microscopic study, immunohistochemistry, and molecular analysis. This patient is the first case with primary EGISTs of prostate received imatinib mesylate as neoadjuvant and adjuvant therapy reported in the literature to date. We hope this case could provide the experience of diagnosis and treatment of primary prostatic EGISTs.

A ganglion-rich gastrointestinal stromal tumor: A case report

We report a case of an extremely rare type of duodenal gastrointestinal stromal tumor (GIST) that included neuronal components. Although gastrointestinal autonomic nerve tumors (GANTs), a subtype of GISTs, exhibit ultrastructural features of the nerve plexus, neuronal cells have not been observed within GANTs or GISTs. GISTs originate from interstitial cells of Cajal (ICCs), which are markedly different from the progenitor cells of neural elements and neural-crest-derived stem cells. This may explain why GISTs typically lack neuronal elements. It remains unclear that the neuronal components of this tumor are neoplastic or hyperplastic, but proliferation and survival of ICCs have recently been reported to be closely related to neurons. Although we could not find the KIT, PDGFR, and BRAF mutation as far as we examined, it may have had a rare mutation in NF1, a fusion of EVT6-NTRK3, or an as-yet-unknown KIT mutation that affected neurogenesis. Further investigation of related genetic mutations and accumulation of data from other similar cases is needed.

Subsequent Development of Desmoid Tumor after a Resected Gastrointestinal Stromal Tumor

Desmoid tumors (deep fibromatosis) of the mesentery are rare mesenchymal tumors. They are often misdiagnosed, especially with a previous history of resection for gastrointestinal stromal tumor (GIST). Immunohistochemistry can help differentiate between these two tumors. In this article, we present a case we had encountered: a Desmoid tumor developing in a patient with a history of GIST 3 years ago. It is the first case of GIST with subsequent development of Desmoid tumor to be reported in Saudi Arabia. We discuss the two entities of Desmoid tumor and GIST by comparing their definitions, clinical presentations, histological features, immunohistochemistry stains, molecular pathogenesis, prognosis, and treatment. We also discuss the relationship between GIST and the subsequent development of Desmoid tumors and compare our case with case reports in literature.

Gastrointestinal Stromal Tumors: A Clinicopathologic and Risk Stratification Study of 255 Cases from Pakistan and Review of Literature

PURPOSE

To describe the clinicopathological features of gastrointestinal stromal tumors (GIST) diagnosed in our section and to perform risk stratification of our cases by assigning them to specific risk categories and groups for disease progression based on proposals by Fletcher et al and Miettinen and Lasota.

MATERIALS AND RESULTS

We retrieved 255 cases of GIST diagnosed between 2003 and 2014. Over 59% were male. The age range was 16 to 83 years with a mean of 51 years. Over 70% occurred between 40 and 70 years of age. Average diameter of tumors was 10 cms. The stomach was the most common site accounting for about 40%. EGISTs constituted about 16%. On histologic examination, spindle cell morphology was seen in almost of 85% cases. CD117 was the most useful immunohistochemical antibody, positive in 98%. Risk stratification was possible for 220 cases. Based on Fletcher's consensus proposal, 62.3 gastric, 81.8% duodenal, 68% small intestinal, 72% colorectal and 89% EGISTs were assigned to the high risk category; while based on Miettinen and Lasota's algorithm, about 48% gastric, 100% duodenal, 76% small intestinal, 100% colorectal and 100% EGISTs in our study were associated with high risk for disease progression, tumor metastasis and tumor related death. Follow up was available in 95 patients; 26 were dead and 69 alive at follow up. Most of the patients who died had high risk disease and on average death occurred just a few months to a maximum of one to two years after initial surgical resection.

CONCLUSIONS

Epidemiological and morphologic findings in our study were similar to international published data. The majority of cases in our study belonged to the high risk category.

Succinate dehydrogenase mutation underlies global epigenomic divergence in gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GIST) harbor driver mutations of signal transduction kinases such as KIT, or, alternatively, manifest loss-of-function defects in the mitochondrial succinate dehydrogenase (SDH) complex, a component of the Krebs cycle and electron transport chain. We have uncovered a striking divergence between the DNA methylation profiles of SDH-deficient GIST (n = 24) versus KIT tyrosine kinase pathway-mutated GIST (n = 39). Infinium 450K methylation array analysis of formalin-fixed paraffin-embedded tissues disclosed an order of magnitude greater genomic hypermethylation relative to SDH-deficient GIST versus the KIT-mutant group (84.9 K vs. 8.4 K targets). Epigenomic divergence was further found among SDH-mutant paraganglioma/pheochromocytoma (n = 29), a developmentally distinct SDH-deficient tumor system. Comparison of SDH-mutant GIST with isocitrate dehydrogenase-mutant glioma, another Krebs cycle-defective tumor type, revealed comparable measures of global hypo- and hypermethylation. These data expose a vital connection between succinate metabolism and genomic DNA methylation during tumorigenesis, and generally implicate the mitochondrial Krebs cycle in nuclear epigenomic maintenance.

An intrapelvic extraintestinal gastrointestinal stromal tumor of undetermined origin: diagnosis by prostate needle biopsy

We herein report a case of intrapelvic gastrointestinal stromal tumor (GIST) of undetermined origin in a 48-year-old male who presented with dysuria. An enlarged tumor was detected on digital rectal examination. Imaging studies showed a solid and lobular homogenous tumor of 7.0 cm in diameter. The tumor was attached to the right dorsal aspect of the prostate with compression of the seminal vesicles and rectum. It was considered that the tumor had arisen from the prostate, although the patient's serum prostate-specific antigen level was low (0.436 ng/mL). The histological diagnosis by prostate needle biopsy was a spindle cell tumor. At cystoprostatectomy, the tumor was confirmed to be separated from the prostate by a fibrous band, and showed spindle cells with a fascicular growth pattern, but without necrotic areas. Mitotic figures were noted in 12 of 50 high-power fields. The tumor cells were immunoreactive for the KIT protein (CD117), CD34, Discovered on GIST-1 (DOG-1), and vimentin. In contrast, they were negative for desmin, α-smooth muscle actin, pancytokeratin (AE1/AE3), and S100 protein. The Ki-67 labeling index was 5%. The genetic analyses targeting the c-kit gene revealed a point mutation at codon 559 (GTT→GAT). The diagnosis of GIST was confirmed on the basis of the morphological features, immunoprofile, and results of the molecular analyses. Since extraintestinal GIST can resemble a prostatic tumor clinically, KIT (CD117) and DOG-1 should be considered for inclusion in the immunohistochemical panel for spindle cell tumors obtained by prostate needle biopsy.

Thoracoscopic treatment of benign esophageal tumors

Introduction

Gastrointestinal stromal tumors are among the most frequent mesenchymal tumors of the gastrointestinal tract; the incidence of these tumors in the esophagus is less than 5%. Prognosis depends on localization, size, mitotic activity and possible invasion of surrounding structures. Minimally invasive surgery may be maximally utilized for removal of these tumors from the esophageal wall. This operation is usually performed thoracoscopically or laparoscopically and using the “rendez-vous” method – with endoscopic navigation.

Aim

To evaluate a set of patients with benign tumor of the esophagus who were operated on at the First Department of Surgery from 2006 to 2011.

Material and methods

In the years 2006-2011 a total of 11 patients with benign tumors of the esophagus underwent operation.

Results

Of the 11 patients with esophageal tumor, 5 were diagnosed with gastrointestinal stromal tumor, 5 with leiomyoma and in one patient the lesion was described as heterotopy of the pancreas. We used the minimally invasive rendez-vous method with endoscopic navigation in 9 cases. All patients healed primarily and were released from hospital on the 4^th-7^th day. These patients are being followed up as outpatients and recurrence of the tumor has not been observed in any of them.

Conclusions

Minimally invasive treatment of benign tumors of the esophageal wall is considered to the method of choice. Due to possible complications and the need for subsequent therapy in some patients, these procedures should be centralized to departments with experience in esophageal, thoracic and minimally invasive surgery.

Tumour Lysis Syndrome Occurring in a Patient with Metastatic Gastrointestinal Stromal Tumour Treated with Glivec (Imatinib Mesylate, Gleevec, STI571)

Tumour lysis syndrome (TLS) is a rare side effect of chemotherapy for solid tumours. It describes the metabolic derangements following rapid and extensive tumour cell death following a good response to chemotherapy. Symptoms are those of metabolic derangement and renal failure. Treatment involves rehydration and correction of metabolic abnormalities. TLS should be considered in high risk groups. We report a case of TLS in a patient with metastatic gastrointestinal stromal tumour treated with imatinib mesylate. To our knowledge, this is the first reported case.

Gastrointestinal stromal tumor with structures resembling intracytoplasmic lumina

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gut. It is characterized by positive immunostaining for CD117, and bears mutations in the c-kit or PDGFRA genes. Its origin remains uncertain. GISTs mainly possess primitive smooth muscle or neuronal differentiation. Although an epithelioid pattern of GIST is a common finding on light microscopy, true epithelial differentiation has never been demonstrated by either immunohistochemistry or ultrastructural study. Here the authors report an epithelioid GIST of the stomach, immunopositive for CD117, DOG1.1, CD34, and PDGFRA, with slight cytoplasmic staining for epithelial membrane antigen. One heterozygous mutation on codon 842 of exon 18 of the PDGFRA gene was also found. Ultrastructurally, tumor cells had plentiful organelles, including some membrane-bound, dense-core granules and cytoplasmic vacuoles. Intermingled thin cellular processes were also found. Unusually, there were many structures resembling glandular epithelial intracellular lumina with processes. The processes, although resembling microvilli, did not have filament cores, while the lumina were either empty or contained some dense or flocculent content of uncertain nature. True intracellular lumina are very rare in GIST and the authors present findings related to this issue, with a discussion on their nature, origin, and significance.

Expression of Ki-67 and cluster of differentiation 34 and 117 in gastrointestinal stromal tumors

AIM: To investigate the clinicopathologic and immunohistochemical features of gastrointestinal stromal tumors (GISTs).

METHODS: A total of 53 cases of GISTs were included in the study. The expression of cluster of differentiation 117 (CD117), cluster of differentiation 34 (CD34), smooth muscle actin (SMA), S-100 protein and Ki-67 in GIST specimens was detected by immunohistochemistry. The clinicopathologic features of GISTs were also analyzed.

RESULTS: Of 53 GIST specimens, 47 were positive for CD117 (47/53, 88.7%), 43 positive for CD34 (43/53, 81.1%), 27 positive for SMA (27/53, 50.9%), 10 positive for S-100 (10/53, 18.9%), and 36 positive for Ki-67 (36/53, 67.9%).

CONCLUSION: Combined detection of CD117 and CD34 can improve the diagnostic accuracy of GISTs. The expression of Ki-67 can be used as a prognostic parameter for GISTs as it is correlated with tumor size and risk.

Rhabdomyosarcoma in the abdominal cavity of a 12-month-old female donryu rat

Neoplasms of skeletal muscle origin are very rare in the rat. Recently, we experienced a case of rhabdomyosarcoma as a white mass involving the junction of the esophagus and stomach in the abdominal cavity of a 12-month-old female Donryu rat. Histopathologically, the neoplastic cells composing the mass invasively spreaded from the lamina propia to the tunica serosa in the stomach as well as the esophagus. Although the neoplastic cells varied in appearance, pleomorphic atypical cells with abundant eosinophilic cytoplasm were prominent. Some tumor cells were stained blue with phosphotungstic acid hematoxylin. The nuclei of spindle-shaped neoplastic cells were arranged longitudinally like beads. Multinucleate giant cells and mitotic figures were also frequently observed. Immunohistochemically, these neoplastic cells were positive for desmin and myoglobin, whereas they were negative for alpha-smooth muscle actin. Taken together these findings, this tumor was diagnosed as a pleomorphic rhabdomyosarcoma, probably derived from the muscle layer of the lower part of the esophagus. This is the first report of rhabdomyosarcoma in a Donryu rat.

Identification of TRAK1 (Trafficking protein, kinesin-binding 1) as MGb2-Ag: a novel cancer biomarker

The present study aimed to describe the characterization of an antibody MGb2 that reacts with an epitope on gastric cancer cells, and identification of MGb2 antigen (MGb2-Ag). Immunostaining revealed its distribution in human tissues and demonstrated that the positive rate of MGb2-Ag was 81.48% in gastric cancer, 100% in gastric signet-ring cell carcinoma and mucinous adenocarcinoma, 13.16% in precancerous conditions, and 0% in chronic superficial gastritis. Using Western blotting, immunoprecipitation and MALDI-TOF MS (matrix assisted laser desorption/ionization time-of-flight mass spectrometry), MGb2-Ag was identified as TRAK1 (Trafficking protein, kinesin-binding 1), a new molecular gained limited recognition. Both MGb2 and commercial anti-TRAK1 Ab recognized prokaryotic expressed TRAK1. Immunostaining characteristics of TRAK1 were identical with MGb2-Ag in continuous sections of paraffin-embedded tissues of gastric tissues. This is the first report that TRAK1/MGb2-Ag is a promising diagnostic marker for gastric cancer and may help to detect signet-ring cell carcinoma and mucinous adenocarcinoma.

Significance of D2-40 expression in the diagnosis of gastrointestinal stromal tumor

We incidentally found the expression of D2-40 in Cajal interstitial cells for the immunohistochemical valuation of lymphatic invasion by gastric and colonic cancer cells. Therefore, we suggested that D2-40 might become an available marker for gastrointestinal stromal tumors (GISTs). In this study, we performed immunohistochemical study of 21 GISTs, As a result, we confirmed a positive reaction for D2-40 in sixteen GISTs. Among sixteen tumors, thirteen tumors were focally positive and remaining three tumors were diffusely positive. We could find no relationship between positive findings for D2-40 and size or location of the tumor. Three of four tumors with intermediate risk of aggressive behavior and two of four tumors with recurrence showed a negative reaction for D2-40. In conclusion, we suggest that D2-40 may be an available marker of GISTs, but the expression of D2-40 seems to be not associated with the degree of risk of aggressive behavior.

Gastrointestinal stromal tumor of the prostate: a case report and literature review

We report a case of gastrointestinal stromal tumor (GIST) of the prostate in a 75-year-old man with dysuria and urinary retention. Digital rectal examination revealed a markedly enlarged prostate. The serum level of prostate-specific antigen was 0.2 ng/dL. Imaging studies showed an expanded prostate, measuring 6.7 x 5.6 x 5.5 cm, with heterogeneity in contrast enhancement. No metastatic disease was found. The pathologic diagnosis of prostatic GIST was made based on characteristic morphological features, immunoprofiles, and molecular analysis. The possibility of secondary involvement by a rectal GIST was excluded by radiological and intraoperative findings. To our knowledge, this is the second case of a primary GIST of the prostate reported in the literature.

A case report of a spontaneous gastrointestinal stromal tumor (GIST) occurring in a F344 rat

We report a case of gastrointestinal stromal tumor (GIST) that developed in a male F344 rat at week 101 of an experiment in a carcinogenicity study. Macroscopically, the primary tumor, which measured 1 cm in diameter, involved the submucosal tissue of the forestomach at the lesser curvature extending to the glandular stomach and esophagus. Histopathologically, the tumor was composed of neoplastic cells with small- to medium-sized spindle-shaped single nuclei and fibrillary cytoplasm lacking distinct cell borders. It invaded extensively into the tunica muscularis and subserosa, further extending to the lamina propria mucosa and serosal surface. A few densely proliferating portions showed a tendency to storiform pattern. Metastatic tumor nodules were found in the liver, spleen, and femur bone marrow, with multiple nodules, up to 1 cm in diameter, apparent in the liver. Immunohistochemically, diffuse, but weak cytoplasmic immunoreactivity for KIT was evident, and most neoplastic cells also exhibited strong immunoreactivity for a -smooth muscle actin and vimentin. Sparse nuclear S-100-immunoreactive cells were further observed, but none of neoplastic cells were immunoreactive for CD34, caldesmon, desmin, cytokeratin, or synaptophysin. Collectively, these features meet the criteria for a GIST, with limited potential for differentiation to smooth muscle and neural cells.

Giant Mesenteric Fibromatosis Presenting as Small Bowel Obstruction

Mesenteric fibromatosis is a proliferative fibroblastic neoplasia of the small intestine mesentery that may occur as a unique or multiple formation. Mesenteric fibromatosis is a rare, locally aggressive neoplasm and may present with abdominal discomfort, abdominal pain, weight loss, or symptoms of ureteral obstruction, mesenteric ischemia, or intestinal obstruction. It is of the utmost importance to distinguish mesenteric fibromatosis from gastrointestinal stromal tumors. Histopathology accurately differentiates between these two distinct entities. The preferred treatment is local surgical excision with a margin of uninvolved tissue. The involvement of important structures like the superior mesenteric artery and the superior mesenteric vein may pose a challenge during resection, but these tumors can be excised and the vessels repaired primarily.

Colorectal mesenchymal tumor: a clinicopathologic study of 25 cases

BACKGROUND

It is important to distinguish gastrointestinal stromal tumors (GISTs) from other gastrointestinal mesenchymal tumors (GIMTs), because of the malignant potential of GISTs and the availability of molecular targeted therapy. GISTs represent the most common subgroup of GIMTs, and rarely occur in the colon and rectum. The first objective of our retrospective study was to reclassify colorectal mesenchymal tumors, from files collected over 20 years, to determine if, based on immunohistologic features, the lesions were truly GISTs. The second objective was to identify the relationship between clinicopathologic features and prognostic factors of GISTs in the colon and rectum.

METHODS

We evaluated all cases of colorectal mesenchymal tumor identified from the database of the Department of Surgical Pathology at Taichung Veterans General Hospital for the period 1983-2001. For 25 patients, clinical data, and information about tumor characteristics, surgical procedures, and survival outcomes, were obtained and analyzed. Histopathologic evaluations, and appropriate immunohistochemical markers, were used to distinguish between various GIMT subtypes. The relationship between KIT expression and clinicopathologic features was investigated.

RESULTS

The following variables were significantly associated with different CD117 results: symptomatic presentation, location, gross features, tumor size, mitotic count, cellularity, and type of surgery. Only 18 tumors were identified as GISTs. For these, the following variables were significantly associated (by univariate analysis) with increased lethality: tumor size (p = 0.049); mitotic count (p = 0.019); nuclear atypia (p = 0.019); and tumor necrosis (p = 0.045). However, only mitotic activity showed a significant difference in the survival analysis (p = 0.0304; log-rank test).

CONCLUSION

Two clinicopathologically different categories were identified from our colorectal mesenchymal tumors: intramural GISTs and polypoid submucosal leiomyomas. Our study suggests that GIST is a better categorization than smooth muscle tumor because of the malignant potential. Prognosis is strictly related to the number of mitoses. However, tumor size, nuclear atypia and tumor necrosis are probably also significant predictive factors of lethality. Future studies with DNA analysis and larger patient numbers are essential to evaluate the prognostic significance of our findings.

Dual CD117 expression in gastrointestinal stromal tumor (GIST) and paraganglioma of Carney triad: a case report

Carney triad is a rare syndrome, with only 20 complete cases reported. We report a 36-year-old white woman with complete Carney triad, including metastatic gastric stromal tumor (GIST), pulmonary chondroma, and nonfunctioning extra-adrenal paraganglioma. Immunohistochemistry was positive for CD34 and CD117 (c-kit) in the GIST, and positive for chromogranin and CD117 in the paraganglioma. Ultrastructural studies demonstrated skeinoid fibers in the GIST. To our knowledge, this is the 21st complete Carney triad case reported and the first report of dual expression CD117 in both GIST and paraganglioma, a finding with intriguing pathogenetic implications related to the organization of the autonomic nervous system.

Analysis of prognostic and immunohistochemical factors in gastrointestinal stromal tumors with malignant potential

The aim of this study was to analyze 37 patients with malignant primary gastrointestinal stromal tumors and to compare the findings and their therapeutic implications with those previously reported. The medical records of 37 patients who were diagnosed and operated on between January 1996 and December 2002 were retrospectively reviewed. The patients' age, tumor size, type of surgery, histologic type, mitotic counts, presence of necrosis, Ki-67 proliferative index, National Institutes of Health 2001 consensus classification, immunohistochemical staining, and recurrence were examined to analyze factors affecting survival. Overall actuarial survival for all patients was 46%. When analyzed by type of resection, the complete resection group (R0 resection) had a mean overall survival of 48.2 +/- 6.18 months compared with the patients with incomplete resection (R1-R2) who survived a mean of 10.8 +/- 3.2 months (P=0.00). Univariate analysis showed development of recurrence (P=0.00), tumor size of 8 cm or greater (P=0.05), Ki-67 proliferative index greater than 0.82 (P=0.0448), desmin staining (P=0.0076), age younger than 49 years (P=0.0009), and incomplete resection (P=0.00) to be significantly correlated with a poor survival. In multivariate analysis, desmin staining (P=0.031), tumor size (P=0.033), age (P=0.01), recurrence (P=0.038), and R0 resection (P=0.02) were significant independent prognostic factors. We recommend that more careful preoperative and more frequent postoperative follow-up examinations be performed for patients with large tumors, age of younger than 49 years, and Ki-67 proliferative index greater than 0.82.

Primary gastrointestinal stromal tumor of the esophagus in an HIV-positive patient

We describe a rare case of malignant gastrointestinal stromal tumor (GIST) of the esophagus presenting in an HIV-positive man. Not only did the tumor arise from an unusual anatomic site for GIST, namely, the esophagus, but it also had a predominant epithelioid cell morphology that is uncommon and preferentially associated with aggressive behavior. Exhaustive immunohistochemical studies showed strong reactivities to the classic GIST marker, CD34, and to the current more sensitive and more specific GIST marker, CD117/ c-kit protein. This immunophenotype corresponded to that of stromal tumors arising in the more common sites like stomach and small intestine as well as to that of a reported series of esophageal GISTs in the general population. Mutations of the c-kit protein was detected in the tumor, confirming previous observations. This further documents that esophageal GIST and the more common benign esophageal spindle cell lesions are pathologically distinct entities and despite its rarity, esophageal GIST should be recognized by pathologists and clinicians. The occurrence of this tumor in an HIV-positive patient is coincidental, and it resulted in an extremely unusual metastatic site that has not been reported for GISTs.