Activating PDGFRA mutations in inflammatory fibroid polyps occur in exons 12, 14 and 18 and are associated with tumour localization

An Inflammatory Fibroid Polyp of the Stomach

An inflammatory fibroid polyp (Vaněk's polyp) is a rare, benign, mesenchymal polyp originating from the submucosa of the gastrointestinal tract. Symptoms are non-specific and depend on the tumor size and location. Despite their benign nature, these tumors can mimic other malignant conditions, making an accurate diagnosis crucial for appropriate management. Histologically, they are submucosal lesions composed of spindle-shaped or stellate stromal cells, stroma with thin-walled vessels around which spindle-shaped cells are arranged similar to onion skin, an eosinophil-rich inflammatory infiltrate, and minimal mitotic activity. In this article, we present the case of a 63-year-old woman with a giant benign inflammatory fibroid polyp of the stomach. We performed distal esophageal resection, total gastrectomy, and omentectomy, as the passage was restored with a transmesocolic termino-lateral esophago-jejunal Roux-en-Y anastomosis. We also present a brief literature review on this topic.

Inflammatory polyp of the ileum causing small bowel intussusception: A case report

Adult intussusception is rare, and an underlying benign or malignant aetiology is often found. Inflammatory fibroid polyp, a benign neoplastic polyp that can arise anywhere in the gastrointestinal tract is a rare cause of intussusception of the small bowel. Clinical presentation differs depending on the location of the lesion in the gastrointestinal tract. Diagnosis may be confirmed on a computed tomography scan or ultrasound. Definite diagnosis is based on histopathology and immunocytochemistry. We present the case of a 58-year-old lady with an inflammatory fibroid polyp who presented with microcytic anaemia and chronic abdominal pain due to recurrent intussusception.

Gastrointestinal Tract Challenges: Chronic Inflammatory Fibroid Polyps Demystified

An inflammatory fibroid polyp (IFP), also known as Vanek's tumor, is an uncommon benign tumor typically found as a solitary, intraluminal polyp in the gastrointestinal (GI) tract. Chronic IFP is characterized by persistent or recurrent inflammatory features, distinct histopathological findings, and a potential for significant GI tract involvement. Typically, IFPs occur predominantly in the gastric antrum, small intestines, and recto-sigmoid colon. They initiate within the submucosal layer and extend into the lamina propria, resulting in a noticeable bulging of the mucosal layer. They may breach the mucosal barrier on rare occasions, leading to ulceration and bleeding. This ongoing bleeding can induce persistent blood loss and symptoms typical of hypovolemic shock. When of smaller size, these growths might be accidentally detected during an endoscopic examination. Conversely, if the lesions are sizable, they can prompt symptoms of obstruction like queasiness, retching, and abdominal discomfort. Here, we present a case of a 47-year-old female who underwent a screening colonoscopy and was found to have an IFP.

Inflammatory fibroid polyp of the renal pelvis: first report at an extra-gastrointestinal site with molecular confirmation

Inflammatory fibroid polyps (IFP) are rare and benign mesenchymal tumours of the gastrointestinal tract. They are submucosal spindle cell lesions with an eosinophilic-rich inflammatory infiltrate and mutations in the platelet-derived growth factor receptor alpha (PDGFRA) gene. In this report, we present the case of a 74-year-old female with a solid tumour of the kidney, which presented as a bland proliferation of spindle cells with thin-walled blood vessels and an inflammatory infiltrate with eosinophilic granulocytes. Immunohistochemistry revealed a positivity for vimentin and a weak staining for CD99 and CD34 in the spindle cells. Because of the morphological similarity to IFPs of the gastrointestinal tract, a molecular pathology analysis was performed. This identified an oncogenic mutation in exon 18 of the PDGFRA gene, which is characteristic for inflammatory fibroid polyps of the gastrointestinal tract. To the best of our knowledge, this is the first case of an IFP in the urogenital tract.

A Rare PDGFRA Exon 15 Germline Mutation Identified in a Patient With Phenotypic Manifestations Concerning for GIST-Plus Syndrome: A Case Report and Review of Literature

Molecular alterations in PDGFRA are well-described as drivers of sporadic gastrointestinal stromal tumors (GISTs) and inflammatory fibroid polyps (IFPs). However, a small number of families with germline PDGFRA mutations in exons 12, 14, and 18 have been reported, forming the basis of an autosomal dominant inherited disorder with incomplete penetrance and variable expressivity, now referred to as PDGFRA-mutant syndrome or GIST-plus syndrome. Phenotypic manifestations of this rare syndrome include multiple gastrointestinal GISTS, IFPs, fibrous tumors, and other variable features. Herein, we report the case of a 58-year-old female who presented with a gastric GIST and numerous small intestinal IFPs, found to harbor a previously undescribed germline PDGFRA exon 15 p.G680R mutation. Somatic tumor testing was performed on the GIST, a duodenal IFP, and an ileal IFP utilizing a targeted next-generation sequencing panel, revealing additional and distinct secondary PDGFRA exon 12 somatic mutations in each of the 3 tumors. Our findings raise important considerations regarding mechanisms of tumor development in patients with underlying germline PDGFRA alterations and highlight the potential utility of expanding currently available germline and somatic testing panels to include exons outside the typical hotspot regions.

Identification of an Activating PDGFRA Deletion in a Novel Sinonasal Soft Tissue Neoplasm

BACKGROUND

Spindle cell tumours in the sinonasal area are diagnostically challenging. We identified a neoplasm that defied histopathological classification using current criteria.

METHODS

The case was subjected to histopathological, immunohistochemical and molecular analysis using a large small variant DNA panel.

RESULTS

The tumour comprised cytologically bland epithelioid spindle cells with a rich vasculature, which lack expression of actin and other smooth muscle markers, CD34 and beta-catenin. An activating insertion/deletion in exon 12 of the PDGFRA gene was detected. This alteration has previously been described in gastrointestinal stromal tumours and inflammatory fibroid polyps of the GI tract, but the site, histological, and immunophenotypic features in this tumour are distinct.

CONCLUSION

We describe a novel sinonasal spindle cell tumour characterised by an activating insertion/deletion in exon 12 of PDGFRA. The diagnosis of PDGFRA-activated sinonasal spindle cell tumour should be considered in difficult to classify mesenchymal lesions at this site.

New insights about the PDGF/PDGFR signaling pathway as a promising target to develop cancer therapeutic strategies

Numerous cancers express platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs). By directly stimulating tumour cells in an autocrine manner or by stimulating tumour stromal cells in a paracrine manner, the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is crucial in the growth and spread of several cancers. To combat hypoxia in the tumour microenvironment, it encourages angiogenesis. A growing body of experimental data shows that PDGFs target malignant cells, vascular cells, and stromal cells to modulate tumour growth, metastasis, and the tumour microenvironment. To combat medication resistance and enhance patient outcomes in cancers, targeting the PDGF/PDGFR pathway is a viable therapeutic approach. There have been reports of anomalies in the PDGF pathway, including the gain of function point mutations, activating chromosomal translocations, or overexpression or amplification of PDGF receptors (PDGFRs). As a result, it has been shown that targeting the PDGF/PDGFR signaling pathway is an effective method for treating cancer. As a result, this study will concentrate on the regulation of the PDGF/PDGFR signaling system, in particular the current methods and inhibitors used in cancer treatment, as well as the associated therapeutic advantages and side effects.

Genetic susceptibility in children, adolescents, and young adults diagnosed with soft-tissue sarcomas

Soft tissue sarcomas (STS) may arise as a consequence of germline variants in cancer predisposition genes (CPGs). We believe that elucidating germline sarcoma predisposition is critical for understanding disease biology and therapeutic requirements. Participation in surveillance programs may allow for early tumor detection, early initiation of therapy and, ultimately, better outcomes. Among children, adolescents, and adults diagnosed with soft-tissue sarcomas and examined as part of published germline sequencing studies, pathogenic/likely pathogenic (P/LP) variants in CPGs were reported in 7-33% of patients. P/LP germline variants were detected most frequently in TP53, NF1 and BRCA1/2. In this review, we describe reported associations between soft tissue sarcomas and germline variants in CPGs, with mentioning of locally aggressive and benign soft tissue tumors that have important associations with cancer predisposition syndromes. We also discuss recommendations for diagnostic germline genetic testing. Testing for sarcoma-predisposing germline variants should be considered as part of the routine clinical workup and care of any child, adolescent, or adult diagnosed with STS and take into account consequences for the whole family.

Jejunal Intussusception Secondary to a Large Inflammatory Fibroid Polyp: A Case Report and Discussion of Differential Diagnosis

Inflammatory fibroid polyp (IFP), initially considered a reactive process, is now recognized as a benign mesenchymal neoplasm of the gastrointestinal tract. We report a case of a 68-year-old woman with medically refractory Crohn disease that presented with intussusception requiring surgical intervention. The resection revealed a jejunal mass consisting of a submucosal proliferation of bland spindle cells in a fibrous stroma infiltrated by numerous eosinophils. By immunohistochemistry, the lesion was positive for vimentin and negative for desmin, smooth muscle actin (SMA), S-100, CD117, DOG1, ALK (D5F3), Melan-A, HMB-45, CD34, and STAT6. Ki-67 proliferative index was low (<1%). The mass was classified as IFP by its characteristic morphology and associated eosinophilia. IFP should be considered in the differential diagnosis of adults with intussusception or bowel obstruction. Definitive treatment typically requires surgical resection of the involved bowel segment.

Inflammatory fibroid polyp of the anus in a 12-month-old girl: Case report and review of the literature

Inflammatory fibroid polyp (IFP) is a rare, usually solitary and intraluminal polypoid benign tumour that can affect any part of the gastrointestinal (GI) tract. Its aetiology is unknown and clinical presentation depends on the site of involvement. We present the case of a 12-month-old girl with IFP and review all reported cases of IFP in children and adolescents <18 years. A 12-month-old girl presented with rectal bleeding. The patient underwent colonoscopy which revealed an anus polyp. Surgical resection was performed and histopathological examination of the specimen showed features of IFP. A literature review of 20 cases (including ours) between 1966 and January 2022 is also presented. To our knowledge, this is the youngest reported patient with IFP and the first in the anal area.

NF1-Associated Inflammatory Polyp of the Colon: First Report of a Sporadic Case

"Juvenile-like (hyperplastic/inflammatory) mucosal polyp" is a term proposed for rare benign mesenchymal lesions of the gastro-intestinal tract so far reported only in patients with type 1 neurofibromatosis (NF1). We report here a first sporadic case of NF1-associated mucosal inflammatory polyp of the colon. The diagnosis was made in a 53-year old female patient with a large polypoid tumor of the cecum. The lesion was predominantly mucosal, made of fibroblast-like cells associated with inflammatory infiltrates rich in eosinophils and containing entrapped, distorted epithelial glands, responsible for the juvenile-like appearance. Whole exome sequencing showed a pathogenic variant of NF1. The patient had no evidence of NF1; no NF1 mutation was detected in normal tissues. Our observation may support the existence of juvenile-like inflammatory polyps associated with NF1 alterations, either germline or somatic. This justifies to test NF1 in difficult-to-classify gastrointestinal mesenchymal tumors.

Combined Ileoileal and Ileocolic Intussusception Secondary to Inflammatory Fibroid Polyp in an Adult: A Case Report

Intestinal intussusception is relatively rare in adults and accounts for approximately 5% of intestinal obstruction. Intussusception is classified into subtypes according to the location, including ileoileal, ileocolic, ileo-ileocolic, colo-colic, jejuno-ileal, or jejuno-jejunal; the ileocolic type being the most common. However, intussusception of a combination of different subtypes has rarely been reported in the available literature. Abdominal computed tomography (CT) is the most accurate tool to evaluate intestinal intussusception. The pathological lead point in the intestine typically results in adult intussusception. Surgical intervention is usually adopted in cases of adult intussusception due to a high incidence of underlying bowel malignancy. An inflammatory fibroid polyp (IFP) is one of the uncommon benign neoplasms of the gastrointestinal (GI) system, which can result in intestinal intussusception. Herein, we present a case of a 50-year-old female with combined ileoileal and ileocolic intussusception, which was initially diagnosed by abdominal CT. Therefore, laparoscopic right hemicolectomy surgery was performed, confirming the final diagnosis as ileoileal and ileocolic intussusception secondary to IFP.

[Mesenchymal tumors and tumor-like lesions of the gastrointestinal tract: an overview]

Mesenchymal tumors and tumor-like lesions of the gastrointestinal (GI) tract are uncommon. They vary from reactive tumefactive lesions and benign neoplasms to highly aggressive sarcomas. Among them, GI stromal tumors (GISTs) are most common, followed, with less frequency, by smooth muscle and neurogenic tumors. The major challenge resides in correctly identifying GISTs and providing a comprehensive report (including risk assessment and genotyping) that represents the basis for an optimized surgical-oncological treatment and/or adjuvant therapy. On the other hand, the challenge of benign lesions is to find a good name (well understandable and reproducible diagnostic term) that helps avoid diagnostic ambiguity and prognostic uncertainty so that overprognostication and overtreatment can be prevented. Moreover, several recently described genetically defined benign and malignant entities need be correctly diagnosed due to their special "targeted" therapeutic options and to further characterize their clinicopathological and biological properties in the future. These recent entities include aggressive epithelioid inflammatory myofibroblastic sarcoma (ALK-RANBP2-driven), malignant gastrointestinal neuroectodermal tumor (EWSR1-ATF1/CREB-related), NTRK-rearranged neoplasms, and, most recently, colorectal NUTM1-rearranged sarcomas. This review highlights the major clinicopathological features of gastrointestinal mesenchymal lesions in light of recent developments.

[Abdominal soft tissue tumors]

Gastrointestinal stromal tumors are the most common mesenchymal tumors in the abdomen and occur in Germany with an incidence of 10 to 15 cases per million inhabitants. Clear identification and characterization are of major importance for the prognosis and therapy of patients. Similarly, they have to be differentiated from other mesenchymal neoplasias such as leiomyomatous, neurogenic, adipocytic, and fibroblastic tumors. Additionally, the number of translocation positive neoplasias is increasing, requiring the use of adequate molecular assays. The aim of this paper is to give practical advice for their identification. Reference pathology is one possibility to support the correct diagnosis.

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.

PDGFRA Immunohistochemistry Predicts PDGFRA Mutations in Gastrointestinal Stromal Tumors

Platelet-derived growth factor receptor A (PDGFRA) is a receptor tyrosine kinase that is activated by mutations in 10% of gastrointestinal stromal tumors (GISTs) and 55% to 70% of inflammatory fibroid polyps. PDGFRA-mutant GISTs are usually epithelioid and occur predominantly in the stomach. Succinate dehydrogenase-deficient GISTs also arise in the stomach and are usually epithelioid, as are some KIT-mutant GISTs. Recently, avapritinib was approved to treat PDGFRA D842V-mutant GISTs, which do not respond to conventional targeted therapy. Here, we evaluate the utility of PDGFRA immunohistochemistry (IHC) to predict PDGFRA mutations to direct targeted therapy. PDGFRA IHC was performed at 1:3000 and 1:10,000 dilutions on a tissue microarray containing 153 GISTs (126 KIT-mutant, 17 PDGFRA-mutant, and 10 succinate dehydrogenase-deficient). The "positive" staining threshold was defined as 50% of neoplastic cells staining at moderate intensity. PDGFRA IHC was 75.0% and 80.9% specific for PDGFRA mutations at 1:3000 and 1:10,000 dilutions, respectively, and it was 100% sensitive at both. On the basis of its higher specificity, a 1:10,000 dilution was used to stain whole-tissue sections of GISTs and other gastric tumor types. Combining tissue microarray and whole-tissue data, PDGFRA IHC was 94.4% sensitive and 81.0% specific for PDGFRA-mutant GIST among all 210 GISTs, and it was 84.1% specific among 149 GISTs with an epithelioid component. PDGFRA was positive in a subset of inflammatory fibroid polyps (15/30; 50%), monophasic synovial sarcomas (5/10; 50%), inflammatory myofibroblastic tumors (5/10; 50%), and plexiform fibromyxomas (2/8; 25%). It was negative in poorly differentiated adenocarcinoma (0/20), diffuse large B-cell lymphoma (0/10), glomus tumor (0/10), gastrointestinal neuroectodermal tumor (0/10), leiomyoma (0/10), gastric schwannoma (0/8), and gastroblastoma (0/3). Among GISTs, PDGFRA IHC is highly sensitive and moderately specific for PDGFRA-mutant tumors; it also can be positive in inflammatory fibroid polyp and some other mesenchymal tumor types. PDGFRA positivity could be used to triage epithelioid GISTs for PDGFRA sequencing to determine optimal therapy.

PDGF receptor mutations in human diseases

PDGFRA and PDGFRB are classical proto-oncogenes that encode receptor tyrosine kinases responding to platelet-derived growth factor (PDGF). PDGFRA mutations are found in gastrointestinal stromal tumors (GISTs), inflammatory fibroid polyps and gliomas, and PDGFRB mutations drive myofibroma development. In addition, chromosomal rearrangement of either gene causes myeloid neoplasms associated with hypereosinophilia. Recently, mutations in PDGFRB were linked to several noncancerous diseases. Germline heterozygous variants that reduce receptor activity have been identified in primary familial brain calcification, whereas gain-of-function mutants are present in patients with fusiform aneurysms, Kosaki overgrowth syndrome or Penttinen premature aging syndrome. Functional analysis of these variants has led to the preclinical validation of tyrosine kinase inhibitors targeting PDGF receptors, such as imatinib, as a treatment for some of these conditions. This review summarizes the rapidly expanding knowledge in this field.

Endoscopic mucosal resection of a large inflammatory fibroid polyp (Vanek's tumor): a case report

Vanek’s Tumor (inflammatory fibroid polyp) is a rare benign mesenchymal lesion occurring throughout the digestive tract. Classical Vanek’s tumor (“gastric”) contains concentric formations of proliferating spindle cells, which are CD34 positive. Atypical-inflammatory pseudotumor-like Vanek’s tumor (“intestinal”) lacks concentric formations and is CD34 negative. A 70-years-old man patient presented during hematochemical routine tests, sideropenic anemia and leukopiastrinosis. The patient performed osteomyelitis biopsy and esophagogastroduodenoscopy (EGD) showing a gastric wall with nodular appearance and, in antrum pre-pyloric, a polypoid pedunculated lesion, measuring approximately 3 cm in diameter, surrounded by hyperemic mucosa. The lesion then was removed by en bloc endoscopic mucosal resection (EMR) and histo-morphological, immune-cytochemical and biomolecular evaluations were performed. The data were compatible with a benign polyp fibroid inflammatory (Vanek’s Tumor). The results of this study suggest that endoscopic mucosal resection is a safe and efficacy solution for the resection of these gastrointestinal polyps and the two morphological patterns of Vanek’s tumor more probably represent only variants of one type of tumor than two different lesions. BRAF mutations were not shown growth PDGFRA wild-type Vanek’s tumor. (www.actabiomedica.it)

Ileal Intussusception in an Adult Caused by a Locally Invasive Inflammatory Fibroid Polyp: A Case Report

Inflammatory fibroid polyps (IFPs) are rare mesenchymal neoplasms affecting the gastrointestinal tract which are considered benign and noninvasive. We present a case of an invasive IFP in a 46-year-old woman who presented with signs of intestinal obstruction due to ileal intussusception. A segment of the small intestine was resected and subsequently intestinal continuity was restored. A polypoid lesion was found obstructing the lumen. Histopathology revealed a mesenchymal proliferation of spindle and stellate cells, without cytological atypia, arranged in a fibromyxoid stroma. The tumor cells were located in the submucosa but also infiltrated the muscularis propria and the subserosa and were CD34 positive. The molecular study by PCR showed mutation in exon 12 of the PDGFRA gene. IFP is considered a true neoplasm and can also be considered as a potentially invasive lesion.

Inflammatory Fibroid Polyp in a 48-Year-Old Male: A Rare Cause of Intussusception

Inflammatory fibroid polyp is a neoplastic condition affecting the gastrointestinal tract and particularly the gastric antrum. It is virtually a benign submucosal mass comprising mesenchymal cells and numerous small blood vessels with inflammatory cells and commonly eosinophils. Patients with inflammatory fibroid polyps usually present clinically with mechanical intestinal obstruction with or without intussusception. Herein, we present a case of a 48-year-old male with a known history of schizophrenia who presented with mechanical intestinal obstruction following intussusception due to inflammatory fibroid polyp involving the proximal jejunojejunal part of the jejunum.

Masquerading in the midgut: a rare diagnosis in a patient with recurrent abdominal pain

A 38-year-old woman who had been previously diagnosed with irritable bowel syndrome was seen in the outpatient clinic with a 2-year history of intermittent cramp-like abdominal pain which was often followed by watery diarrhoea. She had presented several times previously to the emergency department with episodes of severe pain and collapse although on arrival examination findings were mostly unremarkable other than some mild lower abdominal tenderness. On each occasion, the symptoms resolved spontaneously with conservative management. She had been extensively investigated by her general practitioner to establish the cause of her symptoms but all laboratory findings, cross-sectional imaging, ultrasound and oesophagogastroduodenoscopy to date were unremarkable. After being seen in gastroenterology outpatients' clinic, a colonoscopy was performed and was described as being macroscopically normal but microscopic evaluation of colonic biopsies suggested a possible 'resolving infection'. She was treated symptomatically, but within 6 months she represented to hospital with progressively worsening symptoms of severe abdominal pain, now associated with vomiting, followed by watery diarrhoea and then resolution of the symptoms. An abdominal CT scan was performed which showed a small intraluminal-filling defect in the mid-terminal ileum. A wireless capsule endoscopy was organised to further characterise the lesion although this was reported as showing no abnormality. Prior to any further outpatient investigations, she represented as an emergency to hospital in small bowel obstruction, underwent further cross-sectional imaging followed by surgical resection of the lesion. Histological characterisation revealed a small bowel inflammatory fibroid polyp.

Management of small bowel polyps: from small to big

PURPOSE OF REVIEW

Benign small bowel polyps or mass are clinically poorly distinguishable from malignant small bowel masses, and the diagnostic conditions are almost the same. The important point for clinicians is first to take advantage of the different available diagnostic tools to optimize the diagnostic algorithm of a small bowel polyp or mass. Next, according to the clinical situation, associated disease or sporadic situation, the difficulty is to adapt the treatment decision to the patient situation.

RECENT FINDINGS

The last 20 years have been marked by the development of major diagnostic tools for small bowel diseases (capsule endoscopy, cross-sectional imaging with enteroclysis and balloon-assisted enteroscopy) and by the major decrease of intra-operative enteroscopy as a diagnostic mean.

SUMMARY

On the basis of considerable development of capsule endoscopy and the improvement of cross-sectional small bowel imagining, small bowel polyps represent now a frequent clinical situation for gastroenterologists.

Clinical Presentation of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. They constitute 1-2% of all gastrointestinal neoplasms but are the most common subtype of soft tissue sarcomas, accounting for 20-25%. In the late 1990s, GISTs were more and more recognized as a particular tumor entity. The tumors are supposed to originate from the interstitial pacemaker cells of Cajal. They are usually well circumscribed and can be located in every part of the tubular gastrointestinal tract. Most often GISTs occur in the stomach, followed by the small bowel and colon/rectum. In contrast to epithelial tumors, GISTs grow transmurally and submucosal. GISTs can be found with highly variable growth features including tumors with intraluminal, intra- or transmural, and pedunculated appearance. Here we describe the most common clinical presentation of GISTs on the basis of our 809 patients managed from 2004 to 2017. The median age of our patients was 59 years and the average size of GIST was 75 mm (range: 4 mm to 35 cm). The clinical presentation is very heterogeneous, depending on tumor site, size, and growth pattern. GISTs of the stomach is the group with the lowest rate of acute or emergency symptoms with 31%, followed by GISTs of the duodenum with 42%, whereas GISTs of the small bowel show acute symptoms in more than 50% of the cases and have an emergency surgery rate of almost 15%. Many patients are diagnosed accidentally, through screening examinations, or with latent, unspecific symptoms.

Invasive inflammatory fibroid polyp of the stomach: a case report and literature review

Background

Inflammatory fibroid polyps (IFPs) are rare mesenchymal lesions that affect the gastrointestinal tract. IFPs are generally considered benign, noninvasive lesions; however, we report a case of an invasive gastric IFP. To the best of our knowledge, this is only the second case report of an invasive gastric IFP.

Case presentation

A 62-year-old woman presented with complaints of epigastric pain and vomiting. Computed tomography showed a 27-mm, hyper-enhancing tumor in the prepyloric antrum. Upper endoscopy also showed a submucosal tumor causing subtotal obstruction of the gastric outlet. Because a gastrointestinal stromal tumor was suspected, distal gastrectomy was performed. Histopathological examination revealed spindle cell proliferation in the submucosal layer. The spindle cells had invaded the muscularis propria layer and extended to the subserosal layer. The tumor was finally diagnosed as an IFP based on immunohistochemical findings. No mutations were identified in the platelet-derived growth factor receptor alpha (PDGFRA) gene via molecular genetic analysis.

Discussion and conclusions

After the discovery that IFPs often harbor PDGFRA mutations, these growths have been considered neoplastic lesions rather than reactive lesions. Based on the present case, IFPs might be considered not only neoplastic but also potentially invasive lesions.

Expression of cell cycle regulators and frequency of TP53 mutations in high risk gastrointestinal stromal tumors prior to adjuvant imatinib treatment

Despite of multitude investigations no reliable prognostic immunohistochemical biomarkers in GIST have been established so far with added value to predict the recurrence risk of high risk GIST besides mitotic count, primary location and size. In this study, we analyzed the prognostic relevance of eight cell cycle and apoptosis modulators and of TP53 mutations for prognosis in GIST with high risk of recurrence prior to adjuvant treatment with imatinib. In total, 400 patients with high risk for GIST recurrence were randomly assigned for adjuvant imatinib either for one or for three years following laparotomy. 320 primary tumor samples with available tumor tissue were immunohistochemically analyzed prior to treatment for the expression of cell cycle regulators and apoptosis modulators cyclin D1, p21, p16, CDK4, E2F1, MDM2, p53 and p-RB1. TP53 mutational analysis was possible in 245 cases. A high expression of CDK4 was observed in 32.8% of all cases and was associated with a favorable recurrence free survival (RFS), whereas high expression of MDM2 (12.2%) or p53 (35.3%) was associated with a shorter RFS. These results were independent from the primary KIT or PDGFRA mutation. In GISTs with higher mitotic counts was a significantly increased expression of cyclin D1, p53 and E2F1. The expression of p16 and E2F1 significantly correlated to a non-gastric localization. Furthermore, we observed a significant higher expression of p21 and E2F1 in KIT mutant GISTs compared to PDGFRA mutant and wt GISTs. The overall frequency of TP53 mutations was low (n = 8; 3.5%) and could not be predicted by the immunohistochemical expression of p53. In summary, mutation analysis in TP53 plays a minor role in the subgroup of high-risk GIST before adjuvant treatment with imatinib. Strong expression of MDM2 and p53 correlated with a shorter recurrence free survival, whereas a strong expression of CDK4 correlated to a better recurrence free survival.

Inflammatory fibroid polyp of the gastric antrum presenting as hypovolemic shock: Case report and literature review

Inflammatory fibroid polyps (IFP) are an extremely rare entity that arise within the submucosa of the gastrointestinal tract, and represent less than 0.1% of all gastric polyps. They are most commonly localized to the gastric antrum, small intestines and recto-sigmoid colon. IFPs are most commonly found incidentally upon endoscopic evaluation in the absence of symptoms. Presenting symptoms depend on the location of the tumor, although polyps located in the stomach most commonly present with epigastric pain and early satiety. Classic histologic features include perivascular onion skinning of spindle cells with an abundance of eosinophilic infiltration. The prompt diagnosis and management of IFP is essential due to its underlying risk for intussusception, outlet obstruction and acute hemorrhage. In addition, recent evidence has shown that IFP is driven by an activating mutation in the platelet derived growth factor receptor alpha (PDGFRA) gene, suggesting a neoplastic etiology. Herein, we discuss a case of a 65-year-old woman with an inflammatory fibroid polyp of the gastric antrum who initially presented with early hypovolemic shock and melena. Diagnosis was made by endoscopic visualization, biopsy and immunohistochemical analysis.

[Rare etiology of subocclusive syndrome: inflammatory fibroid polyp of the ileum, about a clinical case]

Le polype fibroïde inflammatoire (PFI) est une lésion bénigne rare, qui découle de la sous-muqueuse du tractus gastro-intestinal, apparait généralement comme une lésion bénigne solitaire, localisée rarement au niveau de l'iléon. Son origine est controversée. La présentation clinique varie selon sa localisation, l'invagination et l'obstruction constituent les symptômes révélateurs les plus fréquents quand le polype siège au niveau de l'intestin grêle. Nous rapportons le cas d'un patient âgé de 22 ans, qui présentait une douleur abdominale, des nausées et des vomissements avec des antécédents de constipation intermittente et une perte de poids dans l'année précédente. La radiologie a objectivé une invagination iléo-iléale obstruant complètement la lumière de l'iléon. La résection segmentaire du segment iléal obstrué et l'anastomose termino-terminale ont été effectuées. Le diagnostic final de PFI a été établi par l'examen histologique et immuno-histochimique.

[Gastrointestinal stromal tumors of the stomach and precursor lesions]

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors in the gastrointestinal tract although they are much less frequent than epithelial tumors. In more than 60% of cases they occur in the stomach. Especially small lesions measuring ≤1 cm in diameter, so-called microscopic GIST can occur multifocally, frequently in the proximal stomach wall and sometimes as an incidental finding in a gastrectomy specimen resected for gastric cancer. The multicentricity of GIST alone is not proof of a metastatic behavior or a syndromal or hereditary disease. Multiple sporadic synchronous and metachronous GIST are characterized by different primary mutations mostly in the KIT or PDGFRA genes and are often less aggressive. It is speculative whether a field effect is responsible or whether still unknown GIST-promoting factors may facilitate the development of several independent lesions. If KIT or PDGFRA mutations are lacking, a succinate dehydrogenase (SDH) deficient GIST has to be considered, either hereditary as Carney-Stratakis syndrome or syndromal as part of a Carney triad.

Clinicopathological and molecular features of a large cohort of gastrointestinal stromal tumors (GISTs) and review of the literature: BRAF mutations in KIT/PDGFRA wild-type GISTs are rare events

In KIT/PDGFRA wild-type gastrointestinal stromal tumors (wt-GISTs), BRAF mutations are regarded as alternative pathogenic events driving tumorigenesis. In our study, we aimed at analyzing a large cohort (n=444) of GISTs for BRAF mutations using molecular and immunohistochemical methods. More than 3000 GIST samples from caucasian patients were available in our GIST and Sarcoma Registry NRW. Of these, we selected 172 wt-GISTs to evaluate the frequency of BRAF mutations. Furthermore, 272 GISTs with a representative KIT and PDGFRA mutational status were selected. BRAF mutational status was evaluated by high-resolution melting analysis, Sanger sequencing, and VE1 immunohistochemistry. A BRAF mutation (p.V600E) was found in 7 cases (3.9%) of the wt-GIST cohort. In 2 cases, multiple synchronous tumors harbored the same somatic BRAF mutation. VE1 immunohistochemical staining had a sensitivity of 81.8% and a specificity of 97.5% to detect BRAF p.V600E mutations. Analyzing our cases and the cases reported in the literature (n=37), the percentage of intermediate and high-risk BRAF-mutated wt-GISTs (17/31; 54.8%) was comparable to that recorded for large GIST cohorts irrespective of the mutational status. BRAF mutations are rare events in wt-GISTs, and VE1 immunohistochemistry appears to be a valuable pre-screening tool for the detection of BRAF p.V600E mutations. BRAF mutations in GISTs do not seem to have a prognostic value per se. However, as BRAF inhibition represents a therapeutic option to control disease, we suggest the assessment of the BRAF mutational status, especially in the setting of advanced GIST disease.

Locally infiltrative inflammatory fibroid polyp of the ileum: report of a case showing transmural proliferation

Morphologically, an inflammatory fibroid polyp (IFP) is usually centred in the submucosa. Extension of an IFP to the subserosa with destruction of the muscularis propria is exceedingly rare. Herein, we describe a 70-year-old woman who presented with right lower abdominal pain but was finally diagnosed with an IFP. Contrast-enhanced computed tomography revealed a target-like structure with a hypovascular mass at the leading edge, which was consistent with intussusception due to a tumour. Following surgery, the resected specimen displayed a mass measuring 4 × 3 × 3 cm that was protruding into the lumen. Microscopically, the mass was centred in the submucosa, extending up to the mucosal surface and down to the subserosa and serosa. The muscularis mucosae and muscularis propria were destroyed focally. A PDGFRA gene mutation in exon 2 (1837_1851 del) that was found in this case, as well as a highly infiltrative growth pattern, strongly supported the neoplastic nature of IFP.

Neurofibromatosis Type 1-Associated Inflammatory Polyp of the Gastrointestinal Tract

The entity known as "juvenile-like (inflammatory/hyperplastic) mucosal polyps of the gastrointestinal tract in neurofibromatosis type 1 (NF1)" was recently proposed, but is not well known. Here, we describe the characteristics of this entity in a surgically resected case. The hemorrhagic 2 × 1 cm-sized polyp was resected from the ascending colon of a 55-year-old male NF1 patient. The polyp was composed of characteristic multiple mucosal protrusions and submucosal elements that included vasculopathic changes. Histologically, this lesion was similar to an inflammatory fibroid polyp rather than juvenile or hyperplastic polyps. This disease could be a distinct entity, and "inflammatory vasculopathic polyp" would be a suitable name.

PDGFRA-mutant syndrome

Germline PDGFRA mutations cause multiple heterogeneous gastrointestinal mesenchymal tumors. In its familial form this disease, which was formerly termed intestinal neurofibromatosis/neurofibromatosis 3b (INF/NF3b), has been included among familial gastrointestinal stromal tumors (GISTs) because of its genotype, described when GIST was the only known PDGFRA-mutant gastrointestinal tumor. Shortly afterwards, however, inflammatory fibroid polyps also revealed PDGFRA mutations. Subsequently, gastrointestinal CD34+ 'fibrous tumors' of uncertain classification were described in a germline PDGFRA-mutant context. Our aim was to characterize the syndrome produced by germline PDGFRA mutations and establish diagnostic criteria and management strategies for this hitherto puzzling disease. We studied a kindred displaying multiple gastrointestinal mesenchymal tumors, comparing it with published families/individuals with possible analogous conditions. We identified a novel inherited PDGFRA mutation (P653L), constituting the third reported example of familial PDGFRA mutation. In adult mutants we detected inflammatory fibroid polyps, gastric GISTs and gastrointestinal fibrous tumors of uncertain nosology. We demonstrate that the syndrome formerly defined as INF/NF3b (exemplified by the family reported herein) is simplistically considered a form of familial GIST, because inflammatory fibroid polyps often prevail. Fibrous tumors appear variants of inflammatory fibroid polyps. 'INF/NF3b' and 'familial GIST' are misleading terms which we propose changing to 'PDGFRA-mutant syndrome'. In this condition, unlike KIT-dependent familial GIST syndromes, if present, GISTs are stomach-restricted and diffuse Cajal cell hyperplasia is not observed. This restriction of GISTs to the stomach in PDGFRA-mutant syndrome: (i) focuses oncological concern on gastric masses, as inflammatory fibroid polyps are benign; (ii) supports a selective role of gastric environment for PDGFRA mutations to elicit GISTs, justifying the known predilection for stomach of sporadic PDGFRA-mutant GISTs. An awareness that inflammatory fibroid polyps, relatively common among gastrointestinal mesenchymal tumors, may be the prevailing tumor in PDGFRA-mutant syndrome could eventually reveal an unsuspected prevalence of this condition.

Vanek’s tumor of the small bowel in adults

Inflammatory fibroid polyps (IFPs), or Vanek’s tumor, are one of the least common benign small bowel tumors. IFP affects both sexes and all age groups, with a peak of incidence in the fifth and seventh decades. They can be found throughout the gastrointestinal tract but most commonly in the gastric antrum or ileum. The underlying cause of IFPs is still unknown. Genetic study of IFP showed mutations in platelet derived growth factor alpha in some cases. At the time of diagnosis most IFPs have a diameter of 3 to 4 cm. The lesions have always been recorded as solitary polyps. Symptoms depend on the location and the size of the lesion, including abdominal pain, vomiting, altered small bowel movements, gastrointestinal bleeding and loss of weight. IFPs arising below the Treitz ligament can present with an acute abdomen, usually due to intussusceptions. Abdominal computed tomography is currently considered the most sensitive radiological method to show the polyp or to confirm intussusceptions. Most inflammatory fibroid polyps can be removed by endoscopy. Surgery is rarely needed. Exploratory laparoscopy or laparotomy is frequently recommended as the best treatment for intussusceptions caused by IFP. The operation should be performed as early as possible in order to prevent the intussusceptions from leading to ischemia, necrosis and subsequent perforation of the invaginated bowel segment. This report aims at reviewing the diagnosis, etiology, genetics, clinical presentation, endoscopy, radiology, and best treatment of IFP.

[Molecular pathology of soft tissue tumors: Contribution to diagnosis and therapy prediction]

Soft tissue tumors are often challenging for pathologists on the basis of morphology alone; therefore, tumor-specific chromosomal aberrations, such as translocations and fusions, amplifications or deletions can be diagnostically useful. Fluorescence in situ hybridization is widely used for the detection of most aberrations in routine diagnostics. Furthermore, reverse transcriptase PCR, sequencing and specific immunohistochemical assays are also applied. Next generation sequencing has already contributed to the identification of hitherto unknown aberrations. Molecular pathology is mainly used in sarcomas to discriminate between different tumor entities. In terms of personalized therapy and targeted treatment, molecular pathology can be utilized to detect predictive markers.

An unusual presentation of an inflammatory fibroid polyp of the ileum: A case report

Inflammatory fibroid polyps (IFP) are rare, benign lesions of the gastrointestinal tract. Recent molecular studies of IFPs identified platelet-derived growth factor receptor α (PDGFRA)-activating mutations, suggesting possible neoplastic qualities to IFPs. IFPs originate from the submucosa and often extend into the overlying mucosa. Although certain IFPs infiltrate the muscularis propria focally, disruption of the muscularis propria and penetration into the subserosa is extremely rare. The current study presents an unusual case of an ileal IFP. A 48-year-old female visited the Department of Surgery, Chonbuk National University Hospital (Jeonju, Republic of Korea) due to abdominal pain. Radiological study demonstrated an ileocecal-type intussusception due to a luminal polypoid mass of the ileum. The excised tumor consisted of haphazardly arranged epithelioid and spindled cells in a fibromyxoid stroma, with an abundant vascular network, accompanied by an inflammatory reaction predominantly composed of eosinophilic infiltrates. The infiltrating tumor cells disrupted the muscularis mucosa above the tumor cells and the muscularis propria below the tumor cells, and extended into the subserosa. Immunohistochemically, the tumor cells were positive for vimentin and cluster of differentiation 34, while they were negative for keratin, PDGFRA, smooth muscle actin, desmin, S-100 protein, DOG-1 and c-kit. Sequencing analysis of c-kit exons 9, 11, 13 and 17, and PDGFRA exons 12 and 18 indicated a wild-type status. The patient has remained well for 12 months after surgery without further treatment, with no recurrence of the tumor. Although spread of IFP under the muscularis propria is rare, identification of similar cases and further study will enhance our understanding of the nature of this tumor.

The tyrosine phosphatase SHP2 is required for cell transformation by the receptor tyrosine kinase mutants FIP1L1-PDGFRα and PDGFRα D842V

Activated forms of the platelet derived growth factor receptor alpha (PDGFRα) have been described in various tumors, including FIP1L1-PDGFRα in patients with myeloproliferative diseases associated with hypereosinophilia and the PDGFRα(D842V) mutant in gastrointestinal stromal tumors and inflammatory fibroid polyps. To gain a better insight into the signal transduction mechanisms of PDGFRα oncogenes, we mutated twelve potentially phosphorylated tyrosine residues of FIP1L1-PDGFRα and identified three mutations that affected cell proliferation. In particular, mutation of tyrosine 720 in FIP1L1-PDGFRα or PDGFRα(D842V) inhibited cell growth and blocked ERK signaling in Ba/F3 cells. This mutation also decreased myeloproliferation in transplanted mice and the proliferation of human CD34(+) hematopoietic progenitors transduced with FIP1L1-PDGFRα. We showed that the non-receptor protein tyrosine phosphatase SHP2 bound directly to tyrosine 720 of FIP1L1-PDGFRα. SHP2 knock-down decreased proliferation of Ba/F3 cells transformed with FIP1L1-PDGFRα and PDGFRα(D842V) and affected ERK signaling, but not STAT5 phosphorylation. Remarkably, SHP2 was not essential for cell proliferation and ERK phosphorylation induced by the wild-type PDGF receptor in response to ligand stimulation, suggesting a shift in the function of SHP2 downstream of oncogenic receptors. In conclusion, our results indicate that SHP2 is required for cell transformation and ERK activation by mutant PDGF receptors.

Juvenile-like (inflammatory/hyperplastic) mucosal polyps of the gastrointestinal tract in neurofibromatosis type 1

AIMS

Diffuse neurofibromatosis/ganglioneuromatosis, solitary/plexiform neurofibroma, periampullary carcinoids and gastrointestinal stromal tumour (GIST) are the main gastrointestinal manifestations of neurofibromatosis type 1 (NF-1, von Recklinghausen disease). Inflammatory (juvenile-like) polyps have not been recognised to date as specific gastrointestinal (GI) manifestations of NF-1.

METHODS AND RESULTS

We describe four males aged 23-65 years with NF-1 and inflammatory (juvenile-like) gastrointestinal polyps, and review the literature for similar cases. Two patients had single polyps (sigmoid colon and antrum, respectively), one had two polyps (left colon), and one had three polyps (distal oesophagus and colon). Histological appearances were variable, ranging from juvenile-like to granulation tissue-rich, predominantly inflammatory and hyperplastic. Three lesions showed obliterative vasculopathic changes. None had neurofibromatous or ganglioneuromatous polyps. A review of the literature disclosed 11 similar cases. Most patients presented with severe gastrointestinal symptoms and/or anaemia.

CONCLUSIONS

NF-1-associated inflammatory polyps probably represent specific GI manifestations of this disorder, and should be considered, particularly in patients with GI symptoms. They should be distinguished from inflammatory fibroid polyps and from juvenile-like changes associated with ganglioneuroma/ganglioneuromatosis and neurofibroma/neurofibromatosis. Their aetiology remains obscure, but different mechanisms, including NF-1 inactivation, NF-1-associated vasculopathy, and localised mucosal prolapse/damage caused by motility disorders, might be involved.

Chromosomal aberrations in primary PDGFRA-mutated gastrointestinal stromal tumors

Approximately 15% of gastrointestinal stromal tumors (GISTs) harbor mutations in the platelet-derived growth factor receptor α (PDGFRA) gene. Chromosomal aberrations play a crucial role in tumor progression and correlate with clinical behavior. Imbalances, particularly in PDGFRA-mutated GISTs, have not yet been evaluated in larger series. We analyzed 53 PDGFRA-mutated GISTs (including 2 with corresponding metastases) for chromosomal imbalances by conventional comparative genomic hybridization and compared them with a historical collective of 122 KIT-mutated GISTs. PDGFRA exon 18 mutations (91% of cases) and exon 12 mutations (9% of cases) correlated significantly with gastric and intestinal sites, respectively. The most common aberrations were identical to those found in KIT-mutated GISTs, with -14q in 70%, -1p in 28%, and -22q in 17% of cases. Overall, there were significantly fewer chromosomal aberrations compared with KIT-mutated GISTs, with a mean of 2.8 (0.6 gains, 2.1 losses) aberrations per tumor. There was a statistically significant association of more than 5 chromosomal imbalances with intermediate/high-risk categories. Regarding specific chromosomal aberrations, -9p, -13q, and -22q correlated with intermediate/high risk, and -1p and +8q with poorer survival, although progression occurred in only 2 cases. Altogether, PDGFRA-mutated GISTs display the same chromosomal aberrations as KIT-mutated GISTs, although they have a lower degree of chromosomal instability in line with their generally favorable outcome.

Inflammatory fibroid polyp: a rare benign tumor of the alimentary tract in children presenting as intussusception-case report and review of literature

Inflammatory fibroid polyp (IFP) represents a rare cause of gastrointestinal polypoid disease in childhood. Τhe lesion has been described by various names beyond the currently accepted term, including “Vanek's tumour,” eosinophilic or submucosal granuloma, gastric fibroma with eosinophilic infiltration, inflammatory pseudotumor, and hemangiopericytoma. The etiopathogenesis and origin of the mesenchymal spindle-shaped cells that comprise the polyp remains enigmatic. Recent studies have shown familial occurrence, expression of platelet-derived growth factor receptor (PDGFRA) and oncogenic PDGFRA mutations in the majority of lesions, suggestive of a neoplastic nature. We present a rare case of a 10-year-old boy with an IFP of the terminal ileum, who presented acutely with intussusception and was treated with a right hemicolectomy. Postoperative course was uneventful and the patient has been asymptomatic during follow-up. Histopathology and immunohistochemical analysis excluded inflammatory myofibroblastic tumor (negative for Alk1, desmin, smooth muscle actin [SMA]), gastrointerstinal stromal tumors (GIST) (negative for CD117) and schwannoma (negative for S100). The lesion was positive for CD34 and faintly for vimentin. Despite the classification of IFPs as a mesenchymal benign neoplasm, in the vast majority of cases, surgical excision alone was curative, and no reports exist of a malignant transformation. A cautious approach with periodic surveillance of the affected children seems reasonable though.