Plexiform angiomyxoid myofi broblastic tumor of the stomach

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that we first described in 2007.The tumor is very rare,and to date,only 18 cases confirmed by immunohistochemistry have been reported in the literature.The patients' ages ranged from 7 to 75 years(mean,43 years),and the male-to-female ratio was approximately 1:1.Representative clinical symptoms are ulceration,associated upper gastrointestinal bleeding(hematemesis),and anemia.The tumors are located at the antrum in all cases,and grossly,the tumor is whitish to brownish or reddish,and forms a lobulated submucosal or transmural mass.Microscopically,the tumor is characterized by a plexiform growth pattern,the proliferation of cytologically bland spindle cells,and a myxoid stroma that is rich in small vessels and positive for Alcian blue stain.Immunohistochemically,the tumor cells are positive for α-smooth muscle actin and negative for KIT and CD34.Differential diagnoses include gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract.Some authors proposed that this tumor should be designated as "plexiform fibromyxoma",but this designation might cause confusion.The tumor is probably benign and thus far,neither recurrence nor metastasis has been reported.

Plexiform angiomyxoid myofibroblastic tumor of stomach:A rare case

Plexiform angiomyxoid myofibroblastic tumor(PAMT) is a rare benign mesenchymal tumor of stomach. Rarity of this kind of tumors and scarce review articles may cause underrecognition of this entity and pose a real diagnostic challenge to gastroenterologists, pathologists and surgeons when encountering such patients and differentiating PAMT from other gastric intramural tumors. We report a case of 28-year-old woman, who presented with epigastric pain after meals, iron-deficiency anaemia and weight loss. Upper gastrointestinal endoscopy revealed submucosal tumorlike elevated lesion in the anterior wall of the antrum with intact overlying mucosa. Endoscopic ultrasound showed a 3-cm hypoechoic homogenous mass, originating from the third layer of the gastric wall. Endoscopic ultrasound-guided fine needle aspiration was not informative. Endoscopic buttonhole biopsy was performed to obtain specimens. Following this, the unexpected prolapse of the tumor occurred into the lumen of the stomach, causing gastric outlet obstruction- the biopsy was obtained. Pathomorphological features suggested the diagnosis of PAMT. Gastric resection of the Billroth I type was performed. Diagnosis was confirmed by histological analysis of the surgical specimen.

Plexiform angiomyxoid myofibroblastic tumor treated by endoscopic submucosal dissection:A case report and review of the literature

BACKGROUND Plexiform angiomyxoid myofibroblastic tumor(PAMT)is a rare mesenchymal tumor characterized by multiple nodular plexiform growth patterns and an immunophenotype with myofibroblasts.The pathological characteristics,immunohistochemistry,diagnostic criteria,differential diagnosis,and gene-level changes of PAMT have been reported in many studies.At present,the main treatment for PAMT in the reported cases is surgery;only eight cases were treated via endoscopy(excluding 1 thoracoscopic resection),and the lesions were all smaller than 5 cm.There are no reports on the prognosis and follow-up of young patients with lesion sizes reaching 5 cm who undergo endoscopic submucosal dissection(ESD).Herein,we present the first case of a young patient with a lesion size reaching 5 cm who was diagnosed with PAMT via endoscopic submucosal dissection.CASE SUMMARY A 15-year-old young man with upper abdominal pain for 2 years presented to the Gastroenterology Department of our hospital.Painless gastroscopy showed a semicircular bulge approximately 5 cm in size in the lesser curvature near the cardia of the fundus;the surface was eroded,and shallow ulcers had formed.The pathological manifestations of the biopsy were spindle cell proliferative lesions with interstitial mucinous changes,and the surface mucosa showed chronic inflammatory changes with active lesions;immunohistochemistry showed smooth muscle actin(SMA)(+),CD117(-),CD34(-),DOG-1(-),S-100(-),and Ki67(LI:<1%).We performed ESD on the patient.The lesion that we removed was 5 cm×4 cm×2 cm in size.Pathologically,the resected tissue displayed typical manifestations,such as fat spindle-shaped fibroblasts and myofibroblast-like cells showing irregular nodular hyperplasia.Immunohistochemistry staining of the tumor cells revealed the following:CD34(partially+),SMA(weakly+),CD117(-),DOG-1(-),S-100(-),SDHB(+),PCK(-),and Ki67(labelling index:2%).There was no recurrence or metastasis during the 3-mo follow-up after the operation,and the treatment effect was good.We also performed a review of the literature on the clinical manifestations,pathological features,immunohistochemistry,and differential diagnosis of PAMT.CONCLUSION At present,the diagnostic criteria for PAMT are relatively clear,but the pathogenesis and genetic changes require further study.PAMT is benign in nature,and these patients are less likely to experience local or metastatic recurrence.The main treatment is still surgery if the lesion is in the stomach.Partial gastrectomy and distal gastrectomy are the most frequently performed surgical treatments for PAMT,followed by local resection,subtotal gastrectomy,and wedge resection.But for comprehensive evaluation of the disease,ESD can be considered a suitable method to avoid excessive treatment.

Plexiform Angiomyxoid Myofibroblastic Tumor of the Stomach

Plexiform angiomyxoid myofibroblastic tumor (PAMT) is a recently described gastric tumor with a peculiar plexiform pattern, bland spindle cells and a myxoid stroma rich in arborizing blood vessels. PAMT of the stomach is a very rare tumor without distinctive clinical manifestations. In this study, we report a new case of PAMT which is the first Chinese case in English literature. A 47-year-old Chinese woman was admitted with a 6-month history of intermittent epigastric discomfort, and abdominal pain for 2 months. Gastroscopy showed an elevated mass in the anterior wall of the gastric antrum. Endoscopic ultrasound revealed a focal hypoechoic lesion protruding into the lumen. A laparoscopic distal gastrectomy was performed, and the patient made an uneventful recovery and remains well 1.5 years later. A diagnosis of PAMT was made by histopathology and immunochemistry.

十二指肠丛状血管黏液样肌纤维母细胞瘤一例

本回顾性研究遵守《赫尔辛基宣言》,并经兰州大学第二医院伦理委员会审核批准,免除受试者知情同意,批准文号:2023A-325。患者女,48岁,自述于2022年7月无明显诱因出现间断性黑便,偶有恶心、呕吐,呕吐物为胃内容物,未予特殊处理。

胃丛状血管黏液样肌纤维母细胞瘤2例临床病理观察

目的探讨胃丛状血管黏液样肌纤维母细胞肿瘤(PAMT)的临床病理学特征及诊断、鉴别诊断要点。方法对2例胃丛状血管黏液样肌纤维母细胞肿瘤进行临床病理、免疫组化和电镜研究。结果临床表现为无症状或上腹部不适、疼痛。胃镜示肿物向胃腔内突出。镜下肿瘤在胃壁之间呈结节状、丛状生长,与胃壁平滑肌交错排列,肿瘤富于小的薄壁血管,细胞间富含黏液样或纤维黏液样基质;瘤细胞核呈梭形或卵圆形,核仁不明显,胞质轻度嗜酸性,细胞异型性不明显。免疫组化示肿瘤细胞SMA、MSA和h-caldesmon(+),个别细胞PR(+),CD117、CD34和S-100(-)。电镜示肿瘤有肌纤维母细胞分化。结论胃丛状血管黏液样肌纤维母细胞肿瘤是罕见的肿瘤,具有独特的形态特征,其诊断和鉴别诊断主要依靠病理组织学和免疫组化。

胃丛状纤维黏液瘤临床病理观察

目的探讨胃丛状纤维黏液瘤(PF)的临床病理特征及其鉴别诊断。方法对1例胃PF进行胃镜、组织学观察及免疫组化染色,结合文献讨论其临床病理特点及鉴别诊断。结果患者男性,64岁。左上腹部不适1月余。胃镜示胃窦小弯后壁黏膜下肿物,3.3 cm×2.5 cm大小,边界清晰,表面光滑,色泽正常,顶部凹陷。手术切除肿块。镜下见肿瘤呈多结节状生长,与胃壁平滑肌组织交错分布,富含小的薄壁血管和黏液样基质。肿瘤细胞呈梭形或卵圆形,异型性不明显,未见核分裂象。免疫组化示肿瘤细胞SMA弱(+),CD34、S-100、desmin、CD117和Dog-1(-)。结论胃丛状纤维黏液瘤是一种罕见的有独特组织学特征的胃间叶性肿瘤,熟悉其临床病理学特征有助于与其他胃肠间叶源性肿瘤相鉴别。

Plexiform fibromyxoma of the small bowel: A case report

BACKGROUND Plexiform fibromyxoma is a rare, special type of mesenchymal tumor. The most common presenting symptoms are anemia, hematemesis, and hematochezia, without sex or age predilection. The reported cases have mainly occurred in the gastric antrum and pylorus region, with some cases in the duodenum. CASE SUMMARY We report here a case of plexiform fibromyxoma in the upper segment of the jejunum, which was continuously followed up for 3 years after surgical removal. Plexiform fibromyxoma showed multinodular or plexiform growth. The cells in the tumor node were spindle-shaped but few in number and mitotic figures. Small blood vessels and mucous matrix were found among the tumor cells. Immunohistochemistry revealed that the plexiform fibromyxoma cells were positive for smooth muscle actin, focally positive for CD10, and negative for cytokeratin, CD117, DOG-1(discovered on GIST-1) desmin, S-100, epithelial membrane antigen, and CD34. Ki-67 labeling index was < 5%. Plexiform fibromyxoma showed benign biological behavior. After 3 years of consecutive postoperative follow-up, no obvious signs of metastasis or recurrence were found by imaging examination. CONCLUSION Plexiform fibromyxoma is a rare type of mesenchymal tumor. The diagnosis mainly depends on pathological examination, and it should be distinguished from other gastrointestinal mesenchymal tumors.

Gastric plexiform fibromyxoma resected by endoscopic submucosal dissection after observation of chronological changes:A case report

A 66-year-old man was diagnosed with a gastric submucosal tumor. Endoscopic ultrasound(EUS) revealed an iso/hypoechoic mass in the third layer. No malignant cells were detected in a histological examination. Yearly follow-up endoscopy and EUS showed the slow growth of the tumor. Endoscopic submucosal dissection(ESD) was performed and a glistening tumor was resected. The lesion showed a multinodular plexiform growth pattern consisting of spindle cells with an abundant fibromyxoid stroma that was rich in small vessels. The tumor was diagnosed as plexiform fibromyxoma(PF) by immunohistochemistry. Although difficulties are associated with reaching a diagnosis preoperatively, chronological changes on EUS may contribute to the diagnosis of PF. ESD may also be useful in the diagnosis and treatment of PF.

Rarity among benign gastric tumors: Plexiform fibromyxoma-Report of two cases

Plexiform fibromyxoma is a very rare mesenchymal tumor of the stomach, found almost exclusively in the antrum/pylorus region. The most common presenting symptoms are anemia, hematemesis, nausea and unintentional weight loss, without sex or age predilection. We describe here two cases of plexiform fibromyxoma, involving a 16-year-old female and a 34-year-old male. Both patients underwent complete resection(R0) by distal gastrectomy and retrocolic gastrojejunostomy(according to Billroth 2); for both, the postoperative course was uneventful. Histology showed multiple intramural and subserosal nodules with characteristic plexiform growth, featuring bland spindle cells situated in an abundant myxoid stroma with low mitotic activity. Immunohistochemistry showed α-smooth muscle actin-positive spindle cells, focal positivity for CD10, and negative staining for KIT, DOG1, CD34, S100, β-catenin, STAT-6 and anaplastic lymphoma kinase. One of the cases showed focal positivity for h-caldesmon and desmin. Upon followup, no sign of disease was found. In the differential diagnosis of plexiform fibromyxoma, it is important to exclude the more common gastrointestinal stromal tumors as they have greater potential for aggressivebehavior. Other lesions, like neuronal and vascular tumors, inflammatory fibroid polyps, abdominal desmoid-type fibromatosis, solitary fibrous tumors and smooth muscle tumors, must also be excluded.

胃丛状血管黏液样肌纤维母细胞瘤临床病理特点与预后分析

目的:回顾性分析胃丛状血管黏液样肌纤维母细胞瘤(PAMT)的临床病理特点、诊断及预后。方法:对4例PAMT的临床资料、组织学特点、免疫组化、特殊染色及基因突变进行分析,并结合相关文献讨论。结果:临床症状包括恶心、呕吐、体重减轻、胃部肿块或幽门梗阻。胃镜示黏膜下隆起性肿物,好发于胃窦部。光镜下肿瘤组织呈特征性的丛状或结节状生长于黏膜下胃壁肌层内,结节呈黏液样,大小和形状不一,结节内有增生的肌纤维母细胞和小血管,细胞异型性不明显,核分裂象罕见。4例均有SMA(+),Vimentin(+),Ki-67(1%~3%),其中有2例出现h-caldesmon(弱+)。阿尔辛蓝染色显示细胞间黏液样基质。KIT和PDGFRA突变位点分析显示4例均未出现突变。4例患者均行远端胃切除,术后未见复发转移。结论:PAMT是一种罕见的间叶组织肿瘤,具备良性的生物学行为。

文献中最早获得诊断的胃丛状血管黏液样肌纤维母细胞瘤

Plexiformangiomyxoid myofibroblastic tumor(PAMT)is a rare gastric mesenchymal entity with a peculiar plexiform pattern,bland spindle cells and myxoid stroma rich in arborizing blood vessels.Here we report a 44-year-old Chinese woman with PAMT.Initially she was admitted for removal of a gastric antral‘polyp’found on a routine examination 5 months previously.Our gastroscopy showed a 0.80.8cm polyp-like mass in the antrum which protruded into the lumen.Endoscopic submucosal dissection(ESD)was performed to remove this mass en bloc.The specimen was carefully examined by pathologists,and the correct diagnosis of PAMT was finally made.The tumor in this case depicted typical histopathological and immunohistochemical features of gastric PAMT.This PAMT was not only the smallest on endoscopic examination in the literature but also—unlike the already reported PAMTs—exhibited a focal hyperechogenic lesion on endoscopic ultrasonography(EUS).This information highlights its value on how to identify a PAMT at its early stage.