Plexiform architecture in gastrointestinal stromal tumors is not restricted to succinate dehydrogenase-deficient cases

Accumulating evidence reveals the heterogeneous features of gastrointestinal stromal tumors (GISTs), primarily distinguished by their various molecular triggers defining well characterized subgroups. The identification of the pathogenetic group a given GIST belongs to, in combination with the currently adopted GIST prognosticators, is pivotal for the correct management of GIST patients. Epidemiological, anatomical and morphological features are more or less strictly associated with the various possible GIST molecular pathogenesis; therefore, they can concur to addressing molecular analysis or even influence the identification of GIST subsets by themselves. This is particularly true in a cost/benefit perspective aimed at cutting the expenses of pathology labs. Under these circumstances, a correct classical pathological analysis still appears a fundamental step to achieve an optimal GIST characterization.We herein report a gastric epithelioid PDGFRA-mutant GIST displaying the multinodular/plexiform architecture distinctive of succinate dehydrogenase (SDH)-deficient GISTs. Immunohistochemistry and molecular analysis led to the correct tumor characterization. The reported case constitutes a valuable contribution to GIST pathology in that it demonstrates that multinodular/plexiform architecture is not restricted to SDH-deficient GISTs, but can be found also in PDGFRA-mutant ones; this is an event to be aware of, given the predilection for gastric location and epithelioid morphology shared by these two GIST subgroups, only the latter of which includes imatinib-sensitive cases. Keywords: Gastrointestinal stromal tumor, Platelet-derived growth factor receptor alpha, Multinodular architecture, Plexiform architecture, Succinate dehydrogenas

Telocytes are the physiological counterpart of inflammatory fibroid polyps and PDGFRA-mutant GISTs

PDGFRA mutations in the gastrointestinal (GI) tract can cause GI stromal tumour (GIST) and inflammatory fibroid polyp (IFP). Hitherto no cell type has been identified as a physiological counterpart of the latter, while interstitial Cajal cells (ICC) are considered the precursor of the former. However, ICC hyperplasia (ICCH), which strongly supports the ICC role in GIST pathogenesis, has been identified in germline KIT-mutant settings but not in PDGFRA-mutant ones, challenging the precursor role of ICC for PDGFRA-driven GISTs. Telocytes are a recently described interstitial cell type, CD34+/PDGFRA+. Formerly considered fibroblasts, they are found in many organs, including the GI tract where they are thought to be involved in neurotransmission. Alongside IFPs and gastric GISTs, GI wall \u201cfibrosis\u201d has been reported in germline PDGFRA-mutants. Taking the opportunity offered by its presence in a germline PDGFRA-mutant individual, we demonstrate that this lesion is sustained by hyperplastic telocytes, constituting the PDGFRA-mutant counterpart of germline KIT mutation-associated ICCH. Moreover, our findings support a pathogenetic relationship between telocyte hyperplasia and both IFPs and PDGFRA-mutant GISTs. We propose the term \u201ctelocytoma\u201d for defining IFP, as it conveys both the pathogenetic (neoplastic) and histotypic (\u201ctelocytary\u201d) essence of this tumour, unlike IFP, which rather evokes an inflammatory-hyperplastic lesion

Unusual clear cell tumors of the jaws - clinical and histopathological considerations: a case report

Clear cell neoplasms of the jaw are very infrequent and a review of the literature reports only isolated cases of metastatic renal clear cell carcinoma of the jaw

Epithelioid haemangioendothelioma arising in the nasal cavity

We report here the case of an epithelioid haemangioendothelioma (EHE) arising in the nasal cavity which is, to the best of our knowledge, the first ever described example in the world literature in that particular site. The patient is a 23-year-old male who presented with repeated episodes of epistaxis from the nasal cavity and with a 1.5 cm reddish, polypoid, smooth, spontaneously bleeding nodule in the right middle meatus. This lesion was histologically diagnosed as epithelioid haemangioendothelioma. Immunohistochemically the neoplasm displayed striking positivity for CD31, CD34 and vimentin. A surgical approach was performed by 'facial degloving', removing the right inferior turbinate, the anterior two-thirds of the middle turbinate and the medial wall of the ethmoid bone. After 12 months follow-up the patient is disease-free, without any local or distant recurrence

TRPM7 Is Overexpressed in Human IBD-Related and Sporadic Colorectal Cancer and Correlates with Tumor Grade

Background. Inflammatory bowel disease (IBD) predisposes to colorectal cancer (CRC) with some specific features that distinguish it from sporadic CRC. Magnesium (Mg) homeostasis is severely compromised in IBD patients, which may affect both inflammation and tumor development. Efficient transcellular Mg transport in intestinal cells depends on the transient receptor potential melastatin (TRPM) channels type 6 and 7, but their expression has never been investigated in the context of IBD-related CRC. Aims. We sought to study the expression pattern of TRPM6 and TRPM7 in CRC, and to compare IBD-related cases to sporadic cases. Methods. TRPM6 and TRPM7 protein expression was evaluated by immunohistochemistry in surgical specimens from 16 IBD and 13 NON-IBD CRC patients. Results. TRPM7 expression was higher in tumor tissue than in the adjacent nonneoplastic tissue in both IBD and NON-IBD patients. Overall, adenocarcinomas showed higher TRPM7 expression than adenomas. TRPM7 expression also positively correlated with tumor grade. Conversely, TRPM6 expression was higher in tumor tissues in both IBD and NON-IBD CRC, but it did not correlate with tumor stage or grade. Conclusions. We report possible participation of TRPM6 and 7 in both IBD-related and sporadic CRC and suggest that TRPM7 might serve as a marker of malignant transformation and lack of differentiation

MUC2 but not MUC5 expression correlates with prognosis in radically resected pancreatic cancer patients

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Gastrointestinal juvenile-like (inflammatory/hyperplastic) mucosal polyps in neurofibromatosis type 1 with no concurrent genetic or clinical evidence of other syndromes

Gastrointestinal \u201cjuvenile-like (inflammatory/hyperplastic) mucosal polyps\u201d (JLIHMPs) have been proposed as a neurofibromatosis type 1 (NF1)-specific gastrointestinal manifestation. Juvenile polyposis syndrome (JPS) has also been reported in a NF1 patient, harboring concurrent NF1 and SMAD4 germline mutations. Additionally, NF1-like cafe-au-lait spots have been described in biallelic mismatch repair deficiency, another condition featuring gastrointestinal polyps. The SMAD4 and BMPR1A genes that are involved in 50\u201360% of JPS cases have not been investigated in the ~ 20 published cases of NF1-associated JLIHMPs with the exception of the abovementioned patient with concomitant JPS and NF1. NF1 defects have been found in the only two cases exhaustively tested. Therefore, JLIHMP has been questioned as an independent, NF1-specific entity. Incidental associations between NF1 and gastrointestinal polyposes at risk for gastrointestinal carcinoma should not be overlooked, given their implications in terms of clinical surveillance. We describe two patients featuring JLIHMPs in clinically/genetically proven NF1, in the absence of SMAD4 and BMPR1A mutations. In one case, the intervening mucosa was markedly inflamed, unlike JPS. We suggest that JLIHMP probably represents a gastrointestinal lesion specific to NF1