消化道平滑肌瘤中存在Cajal间质细胞：警惕误诊为胃肠道间质瘤北大核心CSCD

目的探讨消化道平滑肌瘤的临床病理特征,以及Cajal间质细胞（interstitial cells of Cajal,ICC）在消化道平滑肌瘤中的分布特点。方法收集郑州大学第二附属医院2012年6月至2017年6月147例消化道平滑肌瘤临床及病理资料,光镜下观察HE切片,免疫组织化学及奥辛蓝．沙红染色,Sanger测序检测C—KIT和PDGFRA基因突变状态。结果患者年龄13～82岁,平均年龄52岁。男女比例接近1：2。发生于食管100例,胃20例,小肠12例,结直肠15例。组织学上卵圆形或梭形肿瘤细胞呈条束状或编织状排列。肿瘤细胞弥漫阳性表达平滑肌肌动蛋白、结蛋白及h-caldesmon,CD117与DOG1阳性且奥辛蓝-沙红染色阴性的分支状细胞散在分布于肿瘤内,该类细胞见于100％（100／100）食管平滑肌瘤、80％（16／20）胃平滑肌瘤、3／12的小肠平滑肌瘤,所占比例1％～30％不等,而不存在于结直肠平滑肌瘤中。16例CD117与DOG1阳性且奥辛蓝-沙红染色阴性细胞比例≥20％的平滑肌瘤均未检测到C—KIT及PDGFRA基因突变。结论ICC普遍存在于食管、胃及小肠平滑肌瘤中,不能因为肿瘤细胞表达CD117与DOG1而误诊为胃肠道间质瘤,必要时可借助分子检测进行鉴别。     

胃肠道间质瘤中DOG1和nestin的表达及意义

目的:探讨DOG1和nestin在胃肠道间质瘤(gastrointestinal stromal tumor, GIST)中的表达及其诊断价值.方法:采用免疫组织化学EnVision法分别检测25例GIST、5例平滑肌瘤和5例神经鞘瘤中DOG1和nestin的表达.结果:DOG1和nestin在GIST中的阳性表达率分别为100%和88%,而CD117和CD34在GIST中的阳性表达率分别为84%和64%.GIST中DOG1和nestin的表达与肿瘤部位、肿瘤大小、危险度分级和组织学形态均无关(P>0.05).5例平滑肌瘤中DOG1和nestin均阴性表达,DOG1和nestin在神经鞘瘤中的阳性表达率分别为0和100%.DOG1,nestin,CD117和CD34联合检测阳性率为48%.结论:DOG1在诊断GIST中具有敏感性和特异性,而nestin则是GIST诊断中比较敏感的一种标志物,但特异性差.DOG1,nestin,CD117和CD34联合检测可提高GIST的正确诊断.     

食管间质瘤与平滑肌肿瘤对照性研究

目的 探讨食管间质瘤与平滑肌肿瘤临床病理、免疫组织化学及分子生物学特点。方法 24例食管间叶源性肿瘤用CD117、CD34等一组抗体重新进行分类,部分病例同时测定c-kit基因11外显子序列。结果 此组肿瘤分别为间质瘤3例（交界性1例、恶性2例）,年龄71、56、60岁,均为男性,瘤体直径4、8、14cm,源于固有肌层。瘤细胞梭形,上皮样多角形及印戒样,呈交叉束状、栅栏状及弥漫片状排列,免疫表型为CD117、CD34弥漫强阳性。平滑肌瘤20例,年龄30－60岁,平均41.6岁,男性12例,女性8例,15例源于固有肌层,直径0.8-10.5cm（平均4.5cm),5例源于黏膜肌层,直径为0.2-1.0cm(平均0.6cm)。平滑肌肉瘤1例,男性,61例,瘤体直径5cm,源于黏膜肌层。平滑肌（肉）瘤胞质丰富,嗜伊红,交叉束状排列,免疫表型为平滑肌肌动蛋白、肌特异性肌动蛋白、结蛋白弥漫强阳性。恶性间质瘤有c-kit基因11外显子的突变,平滑肌瘤无突变。结论 食管间叶源性肿瘤仍以平滑肌瘤多见,可发生与胃肠道间质瘤相同形态与免疫表型的间质瘤,典型平滑肌肉瘤极为罕见,食管间质瘤与平滑肌瘤具有不同的临床病理学及分子生物学特征。     

胃肠、泌尿、会阴部间质瘤临床病理及免疫组织化学分析

目的 探讨胃肠道间质瘤(GIST)与胃肠道外GIST型间质瘤的组织学起源与病理特征。方法 对46例胃肠道及13例泌尿道、会阴部原诊断平滑肌瘤、平滑肌肉瘤、许旺瘤的病例作回顾性研究,观察其病理特点,应用免疫组织化学方法观察4种抗体(CD117、CD34、平滑肌肌动蛋白、S—100)的表达,对发生于不同部位的间质瘤进行对比分析。结果 45例为GIST组,CD117阳性表达率为93．3％,CD34阳性率88．9％;12例为胃肠道外GIST型间质瘤组,CDll7阳性表达率为83．3％,CD34阳性率75．0％;2例(其中1例为胃肠道)平滑肌瘤组,CDll7和CD34均为阴性,平滑肌肌动蛋白瘤细胞呈弥漫性强阳性表达。结论 CDll7和CD34标记阳性是确诊间质瘤最具有诊断价值的依据。推测GIST和胃肠道外GIST型间质瘤均系起源于一种非定向分化的、原始间充质干细胞。     

小肠间质瘤的免疫组织化学特征其意义

目的探讨小肠间质瘤的临床病理诊断及免疫组织化学特征。方法收集我校附属医院临床病理科6年来对外科手术切除的小肠肿瘤标本,光镜观察、免疫组织化学方法检测Vimentin、desmin、S-100、actin、CD117、CD34和SMA的表达。结果13例肿瘤中良性3例,潜在恶性4例,恶性6例;其中黏膜下生长3例,浆膜下生长5例,肠系膜处生长2例,肌壁内生长3例,常见症状是上腹部肿块和上消化道出血,免疫表形特征为:CD11713例(100%)胞质阳性表达;CD3410例阳性(76.9%)表达,S-100蛋白2例(15.4%)呈局灶表达,10例SMA阴性表达。结论小肠间质瘤发生率较高,多为恶性,有必要和肠的雪旺细胞瘤、平滑肌瘤相区别,CD117、CD34可作为诊断小肠间质瘤免疫标记物,而肿瘤大小、有无出血和坏死、核分裂像等均可作为良恶之判断的参照指标。     

胃肠道间质瘤临床病理研究进展

传统上,胃肠道原发性间叶源性梭形细胞肿瘤几乎都归为平滑肌肿瘤,包括平滑肌瘤与平滑肌肉瘤及它们的各种亚型,但新近研究表明,大多数胃肠道间叶源性肿瘤既不同于典型的平滑肌瘤,也不同于雪旺瘤,而是一组具有不同特征的肿瘤,称为胃肠道间质瘤(ｇａｓｔｒｏｉｎｔｅｓｔｉｎａｌｓｔｒｏｍａｌｔｕｍｏｕｒｓ,ＧＩＳＴｓ)。研究发现较特异和最具实用意义的诊断标准是免疫组织化学检测ｃｋｉｔ基因产物(ＣＤ117)和ＣＤ34的表达〔1,2〕。由于ＧＩＳＴ涵盖了绝大部分胃肠道间叶源性肿瘤,而真正的胃肠道平滑肌瘤及雪旺瘤很少见,因此,作者综合近年…     

P16免疫染色可以提高子宫平滑肌肿瘤的组织学分类

子宫平滑肌肿瘤根据核分裂像、细胞学异型性和凝固性肿瘤细胞坏死可分为平滑肌瘤和平滑肌肉瘤。平滑肌瘤和平滑肌肉瘤是不同的肿瘤，不属于一个生物学谱系。然而，恶性潜能未定的子宫平滑肌肿瘤（STUMP）因缺乏临床经验而不能明确归人平滑肌瘤或平滑肌肉瘤。作者研究了p16在各种子宫平滑肌肿瘤（平滑肌肉瘤15例、平滑肌瘤22例、STUMP8例和10例正常子宫肌层）中的表达，结果显示12／15例平滑肌肉瘤强烈而弥漫性表达p16，     

Wnt/β-catenin信号转导通路在子宫间叶性肿瘤中的表达及其临床意义

目的 探讨子宫间叶性肿瘤组织中Wnt1、β-连环蛋白（β-catenin）、糖原合成酶激酶-3β(GSK-3β)及Slug的表达,并分析其临床意义。方法 回顾性分析唐山市妇幼保健院2016年6月至2021年6月接受手术治疗的50例子宫平滑肌瘤、50例富于细胞性平滑肌瘤、30例子宫肉瘤患者的临床资料,分别记为对照组、富于细胞性平滑肌瘤组、子宫肉瘤组。取手术切除存档的石蜡标本采用免疫组化法检测Wnt1、β-catenin、GSK-3β及Slug表达。结果 富于细胞性平滑肌瘤组、子宫肉瘤组Wnt1、β-catenin、GSK-3β、Slug蛋白阳性表达率均高于对照组（P<0.05）,且子宫肉瘤组均高于富于细胞性平滑肌瘤组（P<0.05）,子宫肉瘤组中子宫平滑肌肉瘤瘤体组织均高于子宫内膜间质肉瘤（P<0.05）,子宫肉瘤组未分化和低级别子宫内膜间质肉瘤瘤体组织均高于高级别子宫内膜间质肉瘤（P<0.05）,且未分化均高于低级别患者（P<0.05）。结论 子宫肉瘤和富于细胞性平滑肌瘤瘤体组织Wnt1、β-catenin、GSK-3β、Slug蛋白表达均较子宫平滑肌瘤增...     

子宫分割性平滑肌瘤1例临床病理分析

目的探讨子宫分割性平滑肌瘤临床病理学特征、诊断及鉴别诊断。方法回顾性分析1例子宫分割性平滑肌瘤的临床病理特征、免疫表型,并复习相关文献。结果患者56岁,B超示盆腔低回声包块,大小15 cm×14 cm×9 cm。MRI示子宫后壁一宫底肌层内肿块影、子宫两旁不规则块状影来源不确定,子宫后壁及双侧附件平滑肌瘤变性?或子宫腺肉瘤合并双侧附件性索来源肿瘤?镜检见肿瘤组织呈分化良好的平滑肌组织形态,沿肌壁局限型分割性生长,无坏死,未见核分裂象,呈丛状分布,平滑肌瘤结节之间明显水肿,平滑肌绕血管或血管丛呈漩涡状或不规则排列。免疫表型:子宫分割性平滑肌瘤瘤细胞表达ER、PR、vimetin、H-caldesmon、desmin、SMA均强阳性,CD34血管阳性,CD117、DOG1、CD10、CD99、HMB-45、S-100、CK和EMA均阴性,Ki-67增殖指数1%。结论子宫分割性平滑肌瘤是平滑肌瘤中极为罕见的亚型,病理诊断尤其是术中冷冻切片易误诊。     

胃肠道Kaposi肉瘤：CD117表达以及误诊为胃肠道问质肿瘤的潜在性

胃肠道Kaposi肉瘤（Ks）的组织学形态可非常类似于胃肠道间质肿瘤（GISTs）。研究表明胃肠道外的KS可以表达CD117（一种常用来帮助GISTs诊断的抗体）。本研究目的是评估胃肠道Ks的临床病理学特征，包括预先加以和未加抗原修复标本中CD117的表达情况。方法和结果：对14例胃肠道KS进行组织学观察，并对其中12例标本进行CD34、人疱疹病毒8（HHV8）、DOG1以及CD117进行免疫组化检测，     

Immunohistochemical spectrum of GISTs at different sites and their differential diagnosis with a reference to CD117 (KIT).

Gastrointestinal (GI) stromal tumor (GIST) is the designation for the major subset of GI mesenchymal tumors and encompasses most tumors previously classified as GI smooth muscle tumors. Although GISTs typically express CD117 (KIT), often express CD34, and sometimes express alpha-smooth muscle actin (SMA), the relative frequency of these markers has not been characterized in large series of GISTs of different sites, and the CD117 expression has not been fully characterized in intra-abdominal tumors. In this study, we immunohistochemically analyzed 292 GISTs throughout the GI tract, including omentum and mesentery, and compared the immunoreactivities with 211 other tumors that may enter in the differential diagnosis. GISTs were defined in this study as CD117-positive primary spindied or epithelioid mesenchymal tumors of the GI tract, omentum, or mesentery. The CD34 positivity of GISTs varied from 47% in small bowel to 96 to 100% in rectum and esophagus, whereas SMA expression showed the opposite patterns and was most frequent in the GISTs of small bowel (47%) and rarest in the GISTs of rectum and esophagus (10-13%). Desmin was seen only occasionally. S100 positivity was rare but was seen most frequently in small intestinal GISTs (15%). True leiomyomas from esophagus, muscularis mucosae of colorectum, and pericolic leiomyomas similar to uterine leiomyomas were negative for CD117 and CD34 and positive for SMA and desmin (46 of 46). Inflammatory fibroid polyps of stomach and small intestine were negative for CD117 but were often positive for CD34 (6 of 8) and variable for SMA (3 of 8). Inflammatory myofibroblastic tumors involving gastric or colonic wall were negative for CD117 but some showed CD117-positive endothelia. GI schwannomas were all negative for CD117 and positive for S100 protein (11 of 11). Extremely focal CD117 positivity was seen in the neoplastic cells of some retroperitoneal leiomyosarcomas and liposarcomas. Among other CD117-positive tumors were intestinal metastatic melanomas (8 of 11) and extraskeletal Ewing's sarcomas (5 of 11), two of which were abdominal. In conclusion, strong CD117 expression defines most primary GI mesenchymal tumors as GISTs, which show different patterns for CD34 and SMA in various parts of the GI tract. Some unrelated CD117-positive tumors (melanomas, Ewing's sarcomas) should not be confused with GISTs.     

Mutations in Exon 11 of c-Kit Occur Preferentially in Malignant versus Benign Gastrointestinal Stromal Tumors and Do Not Occur in Leiomyomas or Leiomyosarcomas

Gastrointestinal stromal tumors (GISTs) comprise the largest subset of mesenchymal tumors of the gastrointestinal tract. These neoplasms differ histologically and immunohistochemically from typical leiomyomas and leiomyosarcomas. Most GISTs express CD34 and CD117 (c-kit protein) but not desmin. Recently, gain-of-function mutations of c-kit proto-oncogene have been shown in five solitary GISTs and in tumors and leukocytes from a family with multiple GISTs. An in-frame deletion or a point mutation in exon 11 of c-kit was detected in these cases. Stable transfection of the mutant c-kit complementary DNA was also shown to induce malignant transformation of murine lymphoid cells, suggesting that the c-kit mutations contribute to tumor development. In this study, we evaluated 43 GISTs and 14 smooth muscle tumors for mutations in the exon 11 of c-kit by a PCR-assay. Half of the malignant GISTs (12/24) and only one benign GIST (1/19) revealed mutant bands. No mutant bands were found in 3 leiomyomas and 11 leiomyosarcomas. Sequence analysis confirmed the presence of an in-frame deletion of 3–21 bp in all 13 GISTs with mutant bands. Wild-type bands from 8 malignant and 11 benign GISTs and 7 smooth muscle tumors without mutant bands were cloned and sequenced. Additional mutations were found in 3 malignant and 2 benign GISTs. There were no mutations in 3 leiomyomas and 4 leiomyosarcomas. The mutation status of exon 11 did not correlate with immunohistochemically detectable expression of the CD117, as virtually all GISTs with or without such mutations showed CD117 immunoreactivity. The c-kit mutations occur preferentially in malignant GISTs and might be a clinically useful adjunct marker in the evaluation of GISTs. The conservation of the c-kit mutation pattern, observed in consecutive lesions from the same patients, suggests that these mutations might be useful tumor markers in monitoring recurrence or minimal residual disease.     

Nestin and caveolin-1 in the diagnosis of GISTs

Gastrointestinal stromal tumors (GISTs) are the most common primary mesenchymal neoplasias of the gastrointestinal tract, typically expressing c-kit (CD117) and CD34. Recently, it was reported that nestin and caveolin-1 are also expressed in some human sarcomas, GISTs included. We performed a retrospective study on formalin fixed, paraffin embedded samples from 81 cases of confirmed GISTs, aiming to characterize their immunohistochemical profile, including nestin and caveolin-1 expressions. Tissue samples were evaluated immunohistochemically for CD117, CD34, nestin and caveolin-1. The patients (M:F 36:45), aged 46 to 84 years, had spindle cell type GISTs in 56.7% of cases, epithelioid in 30.8% and mixed pattern in 12.3%. Immunohistochemically, CD117 was positive in 88.9% of GISTs, CD34 in 85.1%, nestin in 77.7% and caveolin-1 in 71.6% of the tumors. Of nine c-kit negative GISTs, 66.7% expressed nestin, the same as caveolin-1 and 44.5% expressed both nestin and caveolin-1. Statistical analysis using Kendall's and Spearman's tests revealed significant correlations between nestin and caveolin-1 expressions (p=0.024). Our results suggest that nestin and caveolin-1 could be considered sensitive markers in GISTs, together with CD117 and CD34, for diagnostic purposes. Their significant expression in CD117 negative GISTs could represent an immunohistochemical alternative in establishing the diagnosis of these tumors.     

Patterns of nestin and other intermediate filament expression distinguish between gastrointestinal stromal tumors,leiomyomas and schwannomas

The KIT-positive specific gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas are the three most common types of primary mesenchymal tumors of the gastrointestinal (GI) tract. The intermediate filaments are abundant cytoskeletal proteins commonly used as cell differentiation markers in diagnostic immunohistochemistry. Their patterns have not been fully characterized in GI mesenchymal tumors, and could offer differential diagnostically useful parameters. Very recently, nestin, a class VI intermediate filament expressed in neuroectodermal stem cells and skeletal muscle progenitor cells, has been shown in GISTs and suggested as a marker for these tumors. In this study we immunohistochemically examined the expression of nestin and other intermediate filament proteins, including desmin, keratins (Ks), glial fibrillary acidic protein (GFAP), neurofilament, and vimentin in GISTs of different sites, esophageal leiomyomas and GI schwannomas. Nestin was nearly consistently present in GISTs of different locations whether spindle cell or epithelioid, and benign or malignant. It was also detected in 23 of 24 (96%) GI schwannomas, whereas leiomyomas were uniformly negative. Vimentin was present in both GISTs and schwannomas, whereas it was typically absent in leiomyomas (25% positive, usually focally). Desmin was present in all leiomyomas, whereas only 3% of GISTs (4 of 140) were positive, and all schwannomas were negative. K18 was detected in a minority of GISTs, leiomyomas, and schwannomas. Malignant GISTs were more commonly keratin positive than the benign ones; there was 18% K18 positivity in malignant gastric and small intestinal GISTs, but 9% K18 positivity in benign gastric and small intestinal GISTs. Moreover, K8, albeit to a lesser degree, was detected in a minority of GISTs, but K7, K14, K19 and K20 were not detected. GFAP was present in the majority of schwannomas, whereas all GISTs were negative; some leiomyomas had weak cytoplasmic positivity. These results document distinctive patterns of intermediate filament proteins in GI mesenchymal tumors. Nestin is confirmed to be consistently expressed in GISTs but it is also present in most GI schwannomas; GFAP is helpful when separating GISTs and schwannomas, since only the latter are positive. The potential presence of K8 and K18 in GISTs should not lead to the misdiagnosis of carcinoma on biopsy.     

Gastrointestinal spindle cell tumours of the dog: histological and immunohistochemical study

To assess the relevance of spindle cell tumours in the canine gastrointestinal (GI) tract and to classify them, a retrospective study was carried out on haematoxylin and eosin-stained sections from formalin-fixed paraffin wax-embedded samples of 105 primary GI tumours. Seventeen out of 105 (16%) GI tumours were mesenchymal, 48% were epithelial and 36% were round cell tumours. Spindle cell tumours were stained by Masson trichrome, Orcein-Van Gieson and labelled immunohistochemically (vimentin, desmin, smooth muscle actin, protein S100, glial fibrillar acid protein, CD117 and MIB-1) and the histological grade, mitotic index, nuclear size and cellular density were also assessed. The 17 gastrointestinal mesenchymal tumours were classified as 10 leiomyomas (10/10 positive for desmin and smooth muscle actin; 6/10 positive for vimentin) 2 leiomyosarcomas (2/2 positive for desmin, smooth muscle actin and vimentin) and 5 gastrointestinal stromal tumours (GISTs) (5/5 positive for CD117 and vimentin; 3/5 positive for smooth muscle actin). Canine GISTs appeared as densely packed spindle cell tumours, with a diffuse, strong, cytoplasmic immunopositivity for c-kit protein (CD117). GISTs, defined as CD117-positive spindle cell or epithelioid or pleomorphic neoplasms that presumably derive from interstitial cells of Cajal, are reported in recent medical studies as the most common mesenchymal tumours of the GI tract. Our data suggest that GISTs represent a significant portion of canine GI spindle cell tumours, which can be definitely distinguished from leiomyosarcomas only by their expression of CD117.     

L1 (CD171) is highly expressed in gastrointestinal stromal tumors.

The treatment strategy for mesenchymal tumors of the gastrointestinal tract is based upon typing of the tumor. Especially differential diagnosis of gastrointestinal stromal tumors (GISTs) to leiomyomas is crucial for determining radicality of surgery. L1 cell adhesion molecule (CD171) plays an essential role in tumor progression. The aim of this study was to determine expression of L1 in GISTs, smooth muscle tumors, desmoid-type fibromatosis and peripheral nerve sheath tumors (PNSTs). We retrospectively analyzed a total of 129 surgically resected primary tumors or metastases of 72 GISTs, 29 smooth muscle tumors, seven PNSTs and 21 desmoid-type fibromatosis by immunohistochemistry for c-kit, CD34, smooth muscle actin, desmin, vimentin, S-100 and L1 expression. L1 expression was detected in 53 (74%) of 72 GISTs but in none of 29 smooth muscle tumors or 21 desmoid-type fibromatosis (P<0.01 by Fisher's test). In all, four (57%) of seven peripheral nerve sheath tumors were L1-positive. Survival analysis of 55 surgically completely resected GISTs presenting without metastasis at initial diagnosis revealed no tumor-specific death among L1-negative patients (P=0.13 by log-rank test; median follow-up time 41 months) and one recurrence was observed (P=0.12). Interestingly high levels of L1 were seen in tumor vascular endothelial cells of smooth muscle tumors and PNSTs, but not in GISTs. Our data show that L1 is highly expressed in GISTs but not in smooth muscle tumors and desmoid-type fibromatosis being important differential diagnoses. The trend towards a reduced survival of L1-positive patients in this study has to be further evaluated in future trials with higher patient numbers.     

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.     

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.     

Schwannomas of the gastrointestinal tract: clinicopathological features of 12 cases including a case of esophageal tumor compared with those of gastrointestinal stromal tumors and leiomyomas of the gastrointestinal tract

We analyzed the clinicopathological features of 12 gastrointestinal (GI) schwannomas and compared them with those of 37 GI stromal tumors (GISTs) and 15 leiomyomas. Grossly, the schwannomas showed rubbery to firm, yellow-white to tan, glistening, and often trabeculated cut surfaces, resembling soft tissue schwannomas. The GISTs were firm to soft or fish-flesh tan, gray-pink, or variegated tumors with a degenerative change, and the leimyomas resembled typical uterine leiomyomas. Histologically, GI schwannomas were moderately cellular tumors with focal significant nuclear pleomorphism and rare mitotic figures. A characteristic peripheral lymphoid cuff was observed in all cases, but was indistinct in two cases. The GISTs were highly cellular spindle cell, epithelioid or, occasionally, pleomorphic tumors with basophilic appearance. Leiomyomas were paucicellular tumors with eosinophilic appearance. Immunohistochemically, schwannomas were S-100 protein- and glial fibrillary acidic protein (GFAP)-positive, but were negative for c-kit, CD34, and smooth muscle actin (SMA). GISTs were all c-kit- and/or CD34-positive, but GFAP-negative. Leiomyomas were SMA-positive and were negative for c-kit, CD34, S-100 protein, and GFAP. The mean Ki-67 index of schwannoma was 0.7, and those of GIST and leiomyoma were 5.9 and 0.3, respectively. The patients with schwannomas and leiomyomas had a favorable outcome, whereas 12 patients with GISTs showed progression and died of disease. The separation of GISTs from schwannomas is clinically important because the former group has a high risk of malignant behavior. GI schwannomas differed from the conventional soft tissue schwannomas in that they had peripheral lymphoid cuffs, lacked fibrous capsule and vascular hyalinization, and rarely showed degenerative changes. GI schwannomas, however, resembled soft tissue schwannomas in many aspects, and the clinical, gross, histological, and immunohistochemical features were different from those of GISTs and leiomyomas.