Gastrointestinal stromal tumor presenting as a recurrent vaginal mass

Gastrointestinal stromal tumors are CD117 (c-Kit)-positive mesenchymal neoplasms with histologic and ultrastructural features of the interstitial cell of Cajal. While tumors outside of the gastrointestinal tract have been described, to our knowledge the case we present is the first such case in the vagina. We describe a 75-year-old woman with a recurrent vaginal gastrointestinal stromal tumor without apparent rectal involvement. This tumor was characterized by short intersecting fascicles of spindled cells, focal necrosis, and 12 to 15 mitoses per 50 high-power fields. Immunohistochemistry revealed diffuse cytoplasmic positivity for CD117 (c-Kit), CD34, vimentin, and h-caldesmon. Tumor cells were negative for S100, desmin, actin, and CAM 5.2. The differential diagnosis in this case included a vaginal smooth muscle tumor. While histologically similar to a smooth muscle neoplasm, the immunohistochemical profile ruled out smooth muscle differentiation. Gastrointestinal stromal tumor should be considered in the differential diagnosis of vaginal mesenchymal neoplasms.     

PKC theta, a novel immunohistochemical marker for gastrointestinal stromal tumors (GIST), especially useful for identifying KIT-negative tumors

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the digestive tract and the majority of GIST has characteristic gain-of-function mutations of the c-kit gene, which encodes the KIT receptor for stem cell factor. The present study aimed to establish the usefulness of protein kinase C theta (PKC theta) as an immunohistochemical marker for GIST in comparison with KIT immunohistochemistry. PKC theta immunohistochemistry was carried out not only on 48 cases of GIST and another 40 cases of gastrointestinal mesenchymal tumors, but also on 24 cases of various tumors known to be immunohistochemically positive for KIT. Immunohistochemically, 41 out of 48 cases (85%) of GIST were positive for PKC theta, and its expression was confirmed by Western blot analysis using six cases of surgically resected GIST. In the present study there were six GIST immunohistochemically negative for KIT, which histologically revealed a myxoid epithelioid appearance characteristic to that of GIST with platelet-derived growth factor receptor alpha mutation. All six GIST were immunohistochemically positive for PKC theta. No PKC theta immunoreactivity was observed in other gastrointestinal mesenchymal tumors and various KIT-positive tumors except for three cases (14%) of gastrointestinal schwannomas. The present study revealed that PKC theta is an immunohistochemically novel and useful marker for GIST, especially for GIST negative for KIT.     

Increased cyclin D3 expression significantly correlates with p27 nuclear positivity in gastrointestinal stromal tumors

Gastrointestinal stromal tumors, the most common mesenchymal tumors of the gastrointestinal tract, are characterized by strong expression of c-Kit protein. Recently, it has been shown that gastrointestinal stromal tumors may also contain alterations of genes involved in the regulation of cell cycle. In this study, we evaluate the prevalence and clinical significance of cyclin D1 and D3, Ki-67, p27, and retinoblastoma protein expression in a group of 50 human gastrointestinal stromal tumors selected from the files of the Moffitt Cancer Center. Tissue sections from each case were subjected to immunostaining using the avidin-biotin complex method. Cyclin D1 nuclear positivity was detected in 21 of 50 (42%) and cyclin D3 in 24 of 50 (48%) cases. p27 high immunoreactivity and negative or decreased retinoblastoma protein expression were identified in 33 of 50 (66%) gastrointestinal stromal tumors. In 19 of 50 (38%) tumors, Ki-67 had high labeling index. Direct correlation was observed between cyclin D3 and p27 expression (P < .0001), and between cyclin D1 and retinoblastoma protein (P = .03). Coexpression of cyclin D3 and p27 was demonstrated by immunofluorescence. The p27 protein expression inversely correlated with tumor size (P = .004), but was not correlated with tumor grade (P = .12). Ki-67 directly correlated with both tumor size (P = .03) and tumor grade (P = .008). We report a direct correlation between cyclin D3 and p27 expression in gastrointestinal stromal tumors. Additional alterations in cyclin D1, Ki-67, and retinoblastoma protein expression indicate a disregulated cell cycle in these tumors.     

Fine-needle aspiration diagnosis of GIST: a diagnostic dilemma

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. The authors take this opportunity to report two cases of GISTs of large bowel diagnosed on cytology and confirmed by histopathology and immunohistochemistry.     

Nuclear and mitochondrial DNA microsatellite instability in gastrointestinal stromal tumors.

OBJECTIVE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. Nuclear (nMSI) and mitochondrial microsatellite instability (mtMSI) play important roles in tumorigenesis in various organs. The aim of this study was to evaluate the role of nMSI and mtMSI in GISTs. METHODS: Samples from 74 mesenchymal tumors were collected. nMSI and mtMSI were examined by microsatellite assay at BAT26 and D310 mononucleotide repeats in mtDNA, respectively. We compared nMSI, mtMSI and clinicopathologic features, including patient age and sex, tumor location, tumor size, presence of tumor ulceration and presence of distant metastasis, for 51 GISTs for which these data were available. RESULTS: nMSI and mtMSI were detected in 3 (5%) and 10 (16%) of the 62 GISTs, respectively. There was no significant relationship between nMSI, mtMSI and clinicopathologic features. CONCLUSION: These results suggest that mtMSI may play a role, but that nMSI may play little role in the development of GISTs.     

Site-specific epithelial-mesenchymal interactions in digestive neuroendocrine tumors. An experimental in vivo and in vitro study

Little is known about the functional interactions between digestive neuroendocrine tumor cells and their stromal microenvironment. The focus of our study is whether mesenchymal cells modulate peptide expression, cell proliferation, and invasiveness in digestive neuroendocrine tumor cells. We designed an experimental in vivo and in vitro study using the mouse enteroendocrine cell line STC-1. In vivo, STC-1 cells were injected subcutaneously in 18 immunosuppressed newborn rats. At day 21, all animals presented poorly differentiated neuroendocrine tumors with lung metastases. Subcutaneous tumors were usually limited by a capsule containing basement membrane components and myofibroblasts that presented a low mitotic index. Lung tumors were devoid of capsule and poor in myofibroblasts, and their mitotic index was high. The profile of peptide expression in STC-1 tumors was different from that of cultured STC-1 cells. In vitro, STC-1 cells were cultured with fibroblasts of different origins, including dermis, lung, digestive tract, and liver. Based on their origin, myofibroblasts differentially modulated hormone synthesis, proliferation, spreading, and adhesion of STC-1 cells. In conclusion, our results show that site-specific functional interactions between mesenchymal and neuroendocrine cells may contribute to modulating the behavior of digestive neuroendocrine tumors, depending on their growth site.     

人BRDT-NY多克隆抗体的制备及其在消化道肿瘤中的表达检测

目的:构建人BRDT-NY原核表达载体,表达人BRDT-NY原核蛋白,制备其多克隆抗体,检测其在消化道肿瘤中的表达。方法:以质粒pTriplEx2-BRDT-NY为模板,用PCR法扩增人的BRDT-NY基因。将其克隆到原核表达质粒pET28a+中,构建重组质粒pET28a+-BRDT-NY。将该重组质粒转化BL21菌,以IPTG诱导原核蛋白的表达。应用纯化的原核蛋白免疫小鼠,制备多克隆抗体,ELISA测定滴度,并用免疫组织化学法分析该蛋白在消化道肿瘤组织中的表达。结果:成功构建了用于原核蛋白表达的重组质粒,在BL21菌中表达BRDT-NY重组蛋白,用亲和层析Ni柱进行纯化得到人BRDT-NY蛋白。用纯化的BRDT-NY蛋白免疫小鼠2个月后,得到相应的多克隆血清抗体,经ELISA检测,滴度均能达到1/10万。免疫组织化学染色显示BRDT-NY蛋白在消化道肿瘤中有较高的表达率。结论:该抗体的制备为进一步研究BRDT-NY在消化道肿瘤中的发病机制奠定了基础。     

Trends in incidence and survival of mesenchymal neoplasm of the digestive tract within a defined population of northern Norway

Population-based incidence and survival data for gastrointestinal stromal tumor (GIST) are sparse due to the fact that GIST is a rather novel entity both clinically and pathologically, and has not been registered as a separate entity in population-based cancer registries. The aim of the present study was to reclassify all mesenchymal tumors within a defined population of northern Norway over a time-span of 30 years with the purpose of estimating trends of incidence and survival. One hundred and forty-one patients with mesenchymal neoplasms of the digestive tract were identified: 102 as GISTs, 32 as leiomyomatous tumors, 4 as schwannomas, and 3 as fibromas. Incidence rates of GIST showed a significant increase over the whole period, which was not observed for the non-GIST cases. Analysis of GIST cases showed that cases with more than 5 mitoses per 50 high power fields had an increased expected mortality 4 times that of those with fewer mitoses, and the combination of mitotic count and size of tumor can be recommended for categorizing the tumors into different risk levels. The study confirms that GIST is by far the most frequent mesenchymal neoplasm of the digestive tract and that the incidence has increased over the last 30 years.     

nestin在胃肠道间质瘤病理诊断中的价值

目的探讨nestin在胃肠道间质瘤（gastrointestinal stromal tumors,GISTs）辅助诊断中的价值。方法用免疫组化EnVision法检测96例CD117阳性、5例CD117阴性的GISTs,以及食管平滑肌瘤（10例）、消化道雪旺瘤（33例）、肠纤维瘤病（6例）以及腹腔平滑肌肉瘤（15例）,观察这些肿瘤中nestin的表达状况。结果96例CD117阳性的GISTs中,94例表达nestin,其中70例弥漫强表达,21例中度阳性,3例局灶阳性,仅2例阴性;5例CD117阴性的GISTs中,4例表达nestin;33例消化道雪旺瘤中26例表达nestin;15例平滑肌肉瘤中3例局灶表达nestin;10例食管平滑肌瘤、6例肠纤维瘤病均为阴性。结论nestin是辅助诊断GISTs的新指标,可鉴别GISTs与平滑肌肿瘤和纤维瘤病,但在GISTs与雪旺瘤的鉴别中需结合S-100蛋白等指标。     

Molecular analysis of c-Kit and PDGFRA in GISTs diagnosed by EUS

Gastrointestinal stromal tumors (GISTs) are characterized by overexpression and mutations of c-Kit. Approximately 80% of c-Kit mutations occur in exon 11, being a response factor to imatinib (Gleevec) therapy. Mutations of platelet-derived growth factor receptor-alpha (PDGFRA) are observed in a subset of GISTs lacking c-Kit mutations.We aimed to assess whether c-Kit and PDGFRA mutation analysis of GISTs obtained by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) could be routinely performed. Mutation analysis of c-Kit hotspot exons (9, 11, 13 and 17) and PDGFRA hotspot exons (12 and 18) was performed in aspirates of 33 GISTs and 18 non-GIST mesenchymal tumors.Of the GIST cases, 19 (58%) of 33 contained a mutation in exon 11, 1 (3%) in exon 9, and none in exons 13 and 17. No activating c-Kit mutations were identified in non-GIST cases. No PDGFRA mutation was detected.Mutation analysis is possible in these FNA cell blocks and can assist in the diagnosis and therapeutic decisions in GIST cases/     

Giant cell tumor of bone. The role of fibroblast growth factor 3 positive mesenchymal stem cells in its pathogenesis.

OBJECTIVES: Giant cell tumor of bone is typified by massive infiltration of a bland neoplastic stroma by osteoclasts and monocyte progenitors. The current study aimed at evaluating the nature of the neoplastic cells and the mechanisms underlying the massive giant cell recruitment. METHODS: Five different giant cell tumors were evaluated by immunohistochemistry, and explant cell cultures were established from the same tumors. Antigen expression profiles of both the tumors and the derived cultures were assessed. In order to determine if the mesenchymal cells are capable of differentiating into mature osteoblasts, retinoic acid was added to cell cultures and osteocalcin and alkaline phosphatase levels were measured. The proliferative effects of the mesenchymal cells on histiocyte-like cells were evaluated using the U-937 cell line. RESULTS: A large stromal subpopulation expresses fibroblast growth factor receptor 3 (FGF-R3), indicating a mesenchymal origin of these cells. Few cells express bone- or cartilage-specific markers. Cell cultures are predominated by mesenchymal cells, as indicated by a strong staining by FGF R3. Retinoic acid induces osteoblastic differentiation, i.e. osteocalcin expression and alkaline phosphatase production. Conditioned medium of giant-cell-tumor-derived stromal cell cultures induces proliferation of U-937 cells, derived from histiocytic lymphoma. Papain digestion and dialysis of the conditioned media indicates the effector molecule to be a protein over 40 kD in size. The giant cell tumors as well as stromal cell cultures derived from giant cell tumors express osteoprotegerin ligand, the osteoclast activator. CONCLUSIONS: The neoplastic stromal spindle-shaped subpopulation of cells in giant cell tumors are mesenchymal stem cells capable of inducing histiocyte proliferation. Retinoid acid is capable of inducing differentiation of the cells into mature osteoblasts. This should be further investigated in an in vivo model to ascertain whether induction of differentiation will prevent bone loss and retard tumor progression.     

Expression of the intermediate filament nestin in gastrointestinal stromal tumors and interstitial cells of Cajal

It has recently been proposed that gastrointestinal stromal tumors (GISTs) originate from stem cells that differentiate toward a phenotype of interstitial cells of Cajal (ICCs). Nestin is a newly identified intermediate filament protein, and is predominantly expressed in immature cells, such as neuroectodermal stem cells and skeletal muscle progenitor cells, and tumors originating from these cells. In this study, we examined, using immunohistochemistry, the nestin expression in GISTs and ICCs to clarify the origin of GISTs. Strong immunoreactivity for nestin was observed in all 18 GISTs, and its expression was confirmed by Western blot and Northern blot analyses. In contrast, three leiomyomas and a schwannoma that developed in the gastrointestinal tract showed no apparent immunoreactivity for nestin. Among 17 mesenchymal tumors (seven leiomyosarcomas, five malignant peripheral nerve sheath tumors, and five fibrosarcomas) that occurred in sites other than the gastrointestinal tract, only two malignant peripheral nerve sheath tumors were moderately immunoreactive for nestin. Furthermore, with fluorescence double immunostaining of the normal small intestine, nestin expression was demonstrated in ICCs. These results show that nestin may be a useful marker for diagnosis of GISTs, and support the current hypothesis that GISTs are tumors of stem cells that differentiate toward an ICC phenotype.     

Frequency, phenotype, and genotype of minute gastrointestinal stromal tumors in the stomach: an autopsy study

Gastrointestinal stromal tumors are the most common mesenchymal tumors of the human digestive tract. Up to 85% of these tumors show somatic gain-of-function mutation of the receptor tyrosine kinase c-KIT gene. A recent study has shown a high frequency (22.5%) of minute gastrointestinal stromal tumors in stomachs examined during routine autopsies. The aims of our study were to confirm the previously reported incidence of gastric gastrointestinal stromal tumors in routine autopsies and to investigate their molecular alterations. Gastrointestinal stromal tumors were collected prospectively from 578 autopsies over an 18-month period. After recording the size and location of each lesion, representative tissue samples were processed for hematoxylin and eosin staining and immunohistochemically stained for CD117 and CD34. Microdissected DNA from all identified gastrointestinal stromal tumors was studied for c-KIT and platelet-derived growth factor receptor α mutations. We identified 17 gastrointestinal stromal tumors in 578 consecutive autopsies (2.9%) located in the gastric body (47%) and fundus (47%). One tumor location was not recorded. All tumors were immunohistochemically positive for CD117 and CD34. DNA analysis showed c-KIT mutations in 11 cases. One platelet-derived growth factor receptor α mutation was found. The incidence of gastric minute gastrointestinal stromal tumors (2.9%) is higher than the reported clinical incidence. All are benign tumors, and most, including minute tumors, contain c-KIT mutations. This finding highlights the fact that c-KIT mutations are an early event in the evolution of gastrointestinal stromal tumors but are not sufficient per se for clinically relevant disease.     

The unique simultaneous occurrence of granular cell tumor, gastrointestinal stromal tumor, and gastric adenocarcinoma

Granular cell tumors are generally benign oncocytoid lesions of schwannian origin that are often incidental findings in many locations. Gastrointestinal stromal tumors occur in older adults and express the c-Kit protein (CD117). Both of these tumors have been described in association with many other entities; however, they have never been reported to occur jointly. This report is prompted by the simultaneous appearance of 2 granular cell tumors, a gastrointestinal stromal tumor, and a gastric adenocarcinoma in a 65-year-old woman with a history of breast carcinoma and granular cell tumor. To our knowledge, this is the first case report of these tumors occurring simultaneously.     

Endoscopic ultrasound-guided fine-needle aspiration cytology of peripheral nerve-sheath tumors

Endoscopic ultrasound (EUS) has allowed for the fine-needle aspiration and diagnosis of many different gastrointestinal neoplasms, including mesenchymal tumors. Although most mesenchymal tumors of the gastrointestinal tract are gastrointestinal stromal tumors (GISTs), other mesenchymal tumors, including neural tumors, do occur. Proper diagnosis and differentiation of these tumors from GISTs are important because of their different prognoses and treatment regimens. We encountered three peripheral nerve-sheath tumors of the gastrointestinal tract aspirated by EUS (two schwannomas and a granular-cell tumor). We report on the endoscopic ultrasound, cytologic, histologic, and immunohistochemical findings of these cases.     

Length analysis of polymerase chain reaction products: a sensitive and reliable technique for the detection of mutations in KIT exon 11 in gastrointestinal stromal tumors.

Gastrointestinal stromal tumors are the most common mesenchymal neoplasms of the digestive tract. These tumors express the c-kit receptor tyrosine kinase, and many have activating mutations in the juxtamembrane region coded by the exon 11 of KIT. Detection of these mutations has prognostic and therapeutic impact. The aim of the study was to compare a new detection method by length analysis of polymerase chain reaction products (LAPP) to direct sequencing. The detection of either deletion or insertion mutations within the exon 11 of KIT was performed on genomic DNA extracted from 40 paraffin-embedded samples from 38 patients. Double-strand direct sequencing revealed a mutation in 25 of 40 samples. In two additional samples, a mutation was suspected but could not be determined by sequencing. LAPP revealed a mutation in 27 samples, corresponding to the 25 determined and 2 suspected samples. One of these latter samples contained three different alleles. Mutations corresponded to either deletions (n = 24) or insertion (n = 1) and had the same size with sequencing and LAPP. Our results show that LAPP is as accurate and more sensitive than direct sequencing for the detection of deletion or insertion mutations of exon 11 of KIT in gastrointestinal stromal tumors.     

Prognostic factors in malignant gastrointestinal stromal tumors

Gastrointestinal stromal tumors are a heterogeneous group of mesenchymal neoplasms of the gastrointestinal tract in which routine histopathological evaluation fails to reveal definitive evidence of differentiation. Given the heterogeneity in clinical presentation and the frequent morphological overlap, the biological behavior of these neoplasms is difficult to predict. We have evaluated, by Cox Proportional Hazards Regression Analysis, the clinicopathological features of 51 malignant gastrointestinal stromal tumors to identify predictors of survival. In the univariate analysis, survival inversely correlated with size, number of mitoses, and patient's age. In the multivariate analysis, only the degree of necrosis and phenotypic differentiation toward smooth muscle were found to be indicators of poor prognosis. Based on these results, a simple classification scheme for gastrointestinal stromal tumors is proposed. This classification appears to have great prognostic value for these tumors, and may be useful in guiding therapeutic management.     

Differential diagnosis of gastrointestinal stromal tumor and other spindle cell tumors in the gastrointestinal tract based on immunohistochemical analysis

To confirm the usefulness of an immunohistochemical panel of antibodies for KIT (c-kit/CD117), CD34, desmin, smooth-muscle actin (SMA), h-caldesmon (HCD), S-100 protein, neuron-specific enolase (NSE), and beta-catenin, 297 mesenchymal and peripheral nerve-sheath tumors of the gastrointestinal tract and intra-abdominal locations including 211 gastrointestinal stromal tumors (GISTs), 12 leiomyomas, 18 leiomyosarcomas, 17 solitary fibrous tumors (SFTs), 14 schwannomas, and 25 desmoid-type fibromatoses (DTFs) were analyzed immunohistochemically. Consistent (100%) immunoreactivity for KIT, CD34, desmin and S-100, and nuclear accumulation of beta-catenin were detected in GISTs, SFTs, smooth-muscle tumors, schwannomas, and DTFs, respectively. Immunoreactivity for SMA, HCD, and NSE was observed in a wide range of these tumors. In addition, 418 bone and soft tissue tumors were enrolled in this study for KIT immunostaining. As a result, a limited number of these tumors were KIT positive, including synovial sarcoma that showed morphological similarity to GISTs. These findings suggest that KIT, CD34, desmin, S-100, and beta-catenin are key markers for clinical diagnosis of GISTs and other spindle cell tumors that may involve the gastrointestinal tract, whereas SMA, HCD, and NSE have only limited value.     

Immunohistochemistry of desmin and vimentin in smooth muscle tumors of the digestive tract

The expression of desmin and vimentin in 35 "smooth muscle tumors" of the digestive tract was investigated using formalin-fixed and paraffin-embedded materials and the indirect immunoperoxidase method. Fourteen of 15 esophageal tumors and two of 15 gastric tumors were categorized as benign leiomyoma with low cellularity, and immunohistochemically were desmin-positive and vimentin-negative as were normal muscle layers of the digestive tract. The remaining tumors showed moderate to high cellularity: Six tumors seemed to be malignant on the basis of frequent mitosis and/or nuclear atypia, while 11 were considered to be of borderline malignancy. This cellular tumor group exhibited consistent vimentin immunoreactivity, but desmin was negative or only weakly and/or focally positive. S-100 protein was fundamentally negative in these tumors. The pitfalls of studying desmin immunohistochemistry as a routine diagnostic tool in surgical pathology are discussed.