Patient-derived organoids identify an apico-basolateral polarity switch associated with survival in colorectal cancer.

The metastatic progression of cancer remains a major issue in patient treatment. However, the molecular and cellular mechanisms underlying this process remain unclear. Here, we use primary explants and organoids from patients harboring mucinous colorectal carcinoma (MUC CRC), a poor-prognosis histological form of digestive cancer, to study the architecture, invasive behavior and chemoresistance of tumor cell intermediates. We report that these tumors maintain a robust apico-basolateral polarity as they spread in the peritumoral stroma or organotypic collagen-I gels. We identified two distinct topologies - MUC CRCs either display a conventional 'apical-in' polarity or, more frequently, harbor an inverted 'apical-out' topology. Transcriptomic analyses combined with interference experiments on organoids showed that TGFß and focal adhesion signaling pathways are the main drivers of polarity orientation. Finally, we show that the apical-out topology is associated with increased resistance to chemotherapeutic treatments in organoids and decreased patient survival in the clinic. Thus, studies on patient-derived organoids have the potential to bridge histological, cellular and molecular analyses to decrypt onco-morphogenic programs and stratify cancer patients. This article has an associated First Person interview with the first author of the paper.

DKK3 Expression in Glioblastoma: Correlations with Biomolecular Markers.

Glioblastoma is the most common malignant primary tumor of the CNS. The prognosis is dismal, with a median survival of 15 months. Surgical treatment followed by adjuvant therapies such as radiotherapy and chemotherapy characterize the classical strategy. The WNT pathway plays a key role in cellular proliferation, differentiation, and invasion. The DKK3 protein, capable of acting as a tumor suppressor, also appears to be able to modulate the WNT pathway. We performed, in a series of 40 patients, immunohistochemical and Western blot evaluations of DKK3 to better understand how the expression of this protein can influence clinical behavior. We used a statistical analysis, with correlations between the expression of DKK3 and overall survival, age, sex, Ki-67, p53, and MGMT and IDH status. We also correlated our data with information included in the cBioPortal database. In our analyses, DKK3 expression, in both immunohistochemistry and Western blot analyses, was reduced or absent in many cases, showing downregulation. To date, no clinical study exists in the literature that reports a potential correlation between IDH and MGMT status and the WNT pathway through the expression of DKK3. Modulation of this pathway through the expression of DKK3 could represent a new tailored therapeutic strategy in the treatment of glioblastoma.

Deep Submucosal Invasion Is Not an Independent Risk Factor for Lymph Node Metastasis in T1 Colorectal Cancer: A Meta-Analysis.

BACKGROUND & AIMS: Deep submucosal invasion (DSI) is considered a key risk factor for lymph node metastasis (LNM) and important criterion to recommend surgery in T1 colorectal cancer. However, metastatic risk for DSI is shown to be low in the absence of other histologic risk factors. This meta-analysis determines the independent risk of DSI for LNM. METHODS: Suitable studies were included to establish LNM risk for DSI in univariable analysis. To assess DSI as independent risk factor, studies were eligible if risk factors (eg, DSI, poor differentiation, lymphovascular invasion, and high-grade tumor budding) were simultaneously included in multivariable analysis or LNM rate of DSI was described in absence of poor differentiation, lymphovascular invasion, and high-grade tumor budding. Odds ratios (OR) and 95% CIs were calculated. RESULTS: Sixty-seven studies (21,238 patients) were included. Overall LNM rate was 11.2% and significantly higher for DSI-positive cancers (OR, 2.58; 95% CI, 2.10-3.18). Eight studies (3621 patients) were included in multivariable meta-analysis and did not weigh DSI as a significant predictor for LNM (OR, 1.73; 95% CI, 0.96-3.12). As opposed to a significant association between LNM and poor differentiation (OR, 2.14; 95% CI, 1.39-3.28), high-grade tumor budding (OR, 2.83; 95% CI, 2.06-3.88), and lymphovascular invasion (OR, 3.16; 95% CI, 1.88-5.33). Eight studies (1146 patients) analyzed DSI as solitary risk factor; absolute risk of LNM was 2.6% and pooled incidence rate was 2.83 (95% CI, 1.66-4.78). CONCLUSIONS: DSI is not a strong independent predictor for LNM and should be reconsidered as a sole indicator for oncologic surgery. The expanding armamentarium for local excision as first-line treatment prompts serious consideration in amenable cases to tailor T1 colorectal cancer management.

pRB immunostaining in the differential diagnosis between pleomorphic xanthoastrocytoma and glioblastoma with giant cells.

AIMS: Pleomorphic xanthoastrocytoma (PXA) is a rare circumscribed glioma, characterized by frequent BRAF p. V600E mutation, and classified as grade 2 or 3. Owing to overlapping clinical-pathological features, the histological distinction from glioblastoma (GBM) with giant cells (GCs) is challenging. Based on the high frequency of TP53 and RB1 alterations in the latter, this study aimed to assess the value of BRAF, p53, and pRB immunostainings in the differential diagnosis. METHODS AND RESULTS: In 37 GBMs with ≥30% GCs and in eight PXAs, we assessed the alterations of 409 cancer-related genes and immunostainings for BRAF, p53, and pRB. GBMs with GCs were TP53-mutated in 30 cases, RB1-altered in 11, and BRAF-mutated in none. PXAs were BRAF-mutated in six cases, TP53-mutated in three, and RB1-altered in none. pRb immunostaining was lost in 25 GBMs (11 RB1-altered and 14 RB1-unaltered), retained in all PXAs and six GBMs, and inconclusive in six GBMs. pRb loss had 100% specificity and 80.6% sensitivity for GBM with GCs. P53 immunostaining was observed in 22 TP53-mutated GBMs and in one TP53-mutated PXA. It showed 87.5% specificity and 60% sensitivity to identify GBM with GCs. BRAF immunostaining corresponded to BRAF mutation status and it had 100% specificity and 75% sensitivity for detecting PXA. CONCLUSION: This study shows for the first time that loss of pRB immunostaining is sensitive and specific for distinguishing GBM with GCs from PXA in routine practice. Thus, it could complement an immunohistochemical panel that includes BRAF and p53 immunostainings for the differential diagnosis.

Recurrent oligodendroglioma with changed 1p/19q status.

We report a case of oligodendroglioma that had consistent histopathological features as well as a distinct change in 1p/19q status in the second recurrence, after temozolomide chemotherapy and radiotherapy. The first tumor recurrence had oligodendroglial morphology, IDH1 R132H and TERT promoter mutations, and 1p/19q codeletion detected by fluorescent in situ hybridization (FISH). Copy number analysis, assessed by next-generation sequencing, confirmed 1p/19q codeletion, and disclosed loss of heterozygosity (LOH) of chromosomes 4 and 9 and chromosome 11 gain. The second recurrence featured not only oligodendroglial morphology but also the appearance of admixed multinucleated giant cells or neoplastic cells having oval nuclei and mitoses and showing microvascular proliferation; it maintained IDH1 R132H and TERT promoter mutations, acquired TP53 mutation, and showed 19q LOH, but disomic 1p, detected by FISH. Copy number analysis depicted LOH of chromosomes 3p, 13, and 19q, 1p partial deletion (1p chr1p34.2-p11), and gain of chromosomes 2p25.3-p24.1, 8q12.2-q24.3, and 11q13.3-q25. B-allele frequency analysis of polymorphic sites disclosed copy-neutral LOH at 1p36.33-p34.2, supporting the initial deletion of 1p, followed by reduplication of 1p36.33-p34.2 alone. These findings suggest that the two tumor recurrences might have originated from an initial neoplastic clone, featuring 1p/19q codeletion and IDH1 and TERT promoter mutations, and have independently acquired other copy number alterations. The reduplication of chromosome 1p might be the result of temozolomide treatment, and gave rise to false negative 1p deletion detected by FISH. The possibility of 1p copy-neutral LOH should be considered in recurrent oligodendrogliomas with altered 1p/19q status detected by FISH.

Dissecting Stemness in Aggressive Intracranial Meningiomas: Prognostic Role of SOX2 Expression.

Meningiomas are mostly benign tumors that, at times, can behave aggressively, displaying recurrence despite gross-total resection (GTR) and progression to overt malignancy. Such cases represent a clinical challenge, particularly because they are difficult to recognize at first diagnosis. SOX2 (Sex-determining region Y-box2) is a transcription factor with a key role in stem cell maintenance and has been associated with tumorigenesis in a variety of cancers. The purpose of the present work was to dissect the role of SOX2 in predicting the aggressiveness of meningioma. We analyzed progressive/recurrent WHO grade 1−2 meningiomas and WHO grade 3 meningiomas; as controls, non-recurring WHO grade 1 and grade 2 meningioma patients were enrolled. SOX2 expression was evaluated using both immunohistochemistry (IHC) and RT-PCR. The final analysis included 87 patients. IHC was able to reliably assess SOX2 expression, as shown by the good correlation with mRNA levels (Spearman R = 0.0398, p = 0.001, AUC 0.87). SOX2 expression was an intrinsic characteristic of any single tumor and did not change following recurrence or progression. Importantly, SOX2 expression at first surgery was strongly related to meningioma clinical behavior, histological grade and risk of recurrence. Finally, survival data suggest a prognostic role of SOX2 expression in the whole series, both for overall and for recurrence-free survival (p < 0.0001 and p = 0.0001, respectively). Thus, SOX2 assessment could be of great help to clinicians in informing adjuvant treatments during follow-up.

Newly recognised Tumour Types in Glioneuronal tumours according to the 5th edition of the CNS WHO Classification.

Glioneuronal tumours (GNT) are uncommon neoplasms, characterised by glial and neuronal differentiation.In the 5th edition of the World Health Organization (WHO) Classification, they are grouped under the heading "Glioneuronal and neuronal tumours", which comprises fourteen different tumours, among which the diffuse glioneuronal tumour with oligodendroglioma-like cells and nuclear clusters (DGONC), myxoyd glioneuronal tumour (MGT) and multinodular and vacuolating neuronal tumour (MNVNT) are new types.MGT and MNVNT are classified WHO grade 1 and may be recognised and diagnosed by peculiar clinical-pathological features. DGONC was not assigned a WHO grade and was only provisionally included among GNT, due to the possibility that it rather represents an embryonal tumour type or subtype. Although the histopathological characteristics may be useful for its identification, the specific methylation profile is an essential diagnostic criterion for DGONC.

Cytoproliferative activity in colorectal poorly differentiated clusters: Biological significance in tumor setting.

BACKGROUND: Poorly differentiated clusters (PDCs) have gained a significant prognostic role in colorectal carcinomas (CRCs) being associated to high risk of lymph node metastasis, shorter survival time and poor prognosis. The knowledge in PDC biology is not completely clear. MATERIALS AND METHODS: We assessed Ki-67 LI in 45 CRCs showing ≥10 PDCs. We distinguished PDCs at the periphery of the tumor masses (pPDCs) from those within the tumor masses (cPDCs). We chose 3 cut-offs of Ki-67 labeling index (Ki-67 LI): <10%, 10-50%, and >50% of the labeled cells. RESULTS: Ki-67 LI in pPDCs was<10% in 37 cases (82%), 10-50% in 6 cases (13%) and >50%in 2 cases (5%); Ki-67 LI in cPDCs was<10% in 4 cases (23.5%), 10-50% in 4 (23.5%) and >50% in 9 (54%). Ki-67 LI in tumor budding foci (TBs) was <10% in 8 cases (32%), 10-50% in 8 (32%) and >50% in 9 (36%). The difference of Ki-67 LI reaches the statistical significance (p < 0.005). Ki-67 LI <10% in the pPDCs was associated with nodal metastases (pN+) (p < 0.0001), pTNM stage III and IV(p < 0.0001) and TB (p < 0.001). Ki-67 LI > 50% in cPDC was significantly associated withpT3-pT4 and advanced pTNM stages (p < 0.0001), N+ (p = 0.0001) and LVI (p < 0.05). CONCLUSION: Different Ki-67 LI detected between cPDCs and pPDCs suggesting a biological difference in PDCs. An actively proliferating central tumor areas can be distinguished from the peripheral portion of the tumors in which the cells interact with the stroma acquiring invasive and metastatic potential.

Poorly differentiated clusters in colorectal cancer: a current review and implications for future practice.

Poorly differentiated clusters (PDC), defined as small groups of ≥5 tumour cells without glandular differentiation, have gained recent attention as a promising prognostic factor in colorectal cancer (CRC). Numerous studies have shown PDC to be significantly associated with other adverse histopathological features and worse clinical outcomes. PDC may hold particular promise in stage II colon cancer, where risk stratification plays a critical role in patient selection for adjuvant chemotherapy. In addition, emerging evidence suggests that PDC can predict lymph node metastasis in endoscopically resected pT1 CRC, potentially helping the selection of patients for oncological resection. In 'head-to-head' comparisons, PDC grade has consistently outperformed conventional histological grading systems both in terms of risk stratification and reproducibility. With a number of large-scale studies now available, this review evaluates the evidence regarding the prognostic significance of PDC, considers its relationship with other emerging invasive front prognostic markers (such as tumour budding and stroma type), assesses its 'practice readiness', addressing issues such as interobserver reproducibility, scoring methodologies and special histological subtypes (e.g. micropapillary and mucinous carcinoma), and draws attention to ongoing challenges and areas in need of further study. Finally, emerging data on the role of PDC in non-colorectal cancers are briefly considered.

Diffuse gliomas in patients aged 55 years or over: A suggestion for IDH mutation testing.

Diffuse gliomas are defined on the isocitrate dehydrogenase (IDH) gene (IDH) mutational mutational status. The most frequent IDH mutation is IDH1 R132H, which is detectable by immunohistochemistry; other IDH mutations are rare (10%). IDH mutant gliomas have better prognosis. Further, IDH wild-type low-grade (II/III) gliomas have clinical behaviors similar to those of glioblastoma (GBM) and it was suggested that they are submitted to similar post-surgical treatment. The incidence of IDH mutant gliomas (2%) and that of GBMs with non-canonical IDH mutations (< 1%) are very low in patients ≥ 55 years. For this reason, it was suggested that immunohistochemistry against IDH1 R132H is sufficient to classify GBM as IDH wild-type in this age group. However, no indication was provided for IDH mutational testing in low-grade diffuse gliomas. To address this issue, 273 diffuse gliomas were tested for IDH1 R132H immunohistochemistry. 2/4 diffuse astrocytomas (DAs), 4/9 anaplastic astrocytomas (AAs), 2/256 GBMs, and 4/4 oligodendrogliomas had positive staining. No other IDH mutations were found in immuno-negative low-grade cases by DNA sequencing. To validate our findings, we considered 311 diffuse gliomas in patients ≥ 55 years in The Cancer Genome Atlas database. Fifty-five out of 311 gliomas had IDH R132H mutations (9/16 DAs; 8/48 AAs; 3/211 GBMs; 35/36 oligodendrogliomas), one DA, and one oligodendroglioma had other IDH mutations. IDH mutant gliomas had significantly higher frequency of O-6-methylguanine-DNA methyltransferase promoter methylation (P = 0.0008) and longer overall survival (P < 0.0001). In conclusion, low-grade gliomas are a minor part of gliomas (117/584) in patients ≥ 55 years, albeit they represent most IDH mutant gliomas in this age group (64/69 cases). IDH non-canonical mutations can be found in immunonegative low-grade gliomas (2/54). In view of its significance for prognosis and therapeutic management, our results suggest that IDH mutational status is assessed in all diffuse gliomas in patients ≥ 55 years by immunohistochemistry, followed by IDH sequencing in low-grade immunonegative cases.

Impact of image analysis and artificial intelligence in thyroid pathology, with particular reference to cytological aspects.

OBJECTIVE: Thyroid pathology has great potential for automated/artificial intelligence algorithm application as the incidence of thyroid nodules is increasing and the indeterminate interpretation rate of fine-needle aspiration remains relatively high. The aim of the study is to review the published literature on automated image analysis and artificial intelligence applications to thyroid pathology with whole-slide imaging. METHODS: Systematic search was carried out in electronic databases. Studies dealing with thyroid pathology and use of automated algorithms applied to whole-slide imaging were included. Quality of studies was assessed with a modified QUADAS-2 tool. RESULTS: Of 919 retrieved articles, 19 were included. The main themes addressed were the comparison of automated assessment of immunohistochemical staining with manual pathologist's assessment, quantification of differences in cellular and nuclear parameters among tumour entities, and discrimination between benign and malignant nodules. Correlation coefficients with manual assessment were higher than 0.76 and diagnostic performance of automated models was comparable with an expert pathologist diagnosis. Computational difficulties were related to the large size of whole-slide images. CONCLUSIONS: Overall, the results are promising and it is likely that, with the resolution of technical issues, the application of automated algorithms in thyroid pathology will increase and be adopted following suitable validation studies.

5-ALA False-Positive in Anaplastic Oligodendroglioma, IDH-mutant and 1p/19q-codeleted.

Pr5-ALA has been well-established for use in intraoperative fluorescence-guided resection of malignant glioma. It is not as strongly supported for use with low-grade gliomas (LGG) because only a few of these, less than 20%, have visible porphyrin accumulation, which is useful for 5-ALA-guided surgery. We report here our experience with 5-ALA uptake in a case of suspected relapse of anaplastic oligodendroglioma, IDH-mutant and 1p/19q-codeleted.

High p-mTOR expression is associated with recurrence and shorter disease-free survival in atypical meningiomas.

Due to their widely variable clinical behavior, the post-surgical treatment of atypical meningiomas is controversial. Therefore, prognostic factors able to identify high-risk cases, which may benefit from adjuvant treatments, are warranted. Mammalian target of rapamycin (mTOR) belongs to the PI3K-AKT pathway. Its phosphorylated form (p-mTOR Ser2448) is involved in cell growth, differentiation and tumorigenesis. The aim of this study was to evaluate p-mTOR Ser2448 expression and its eventual correlation with clinicopathological features, recurrence, or disease-free survival (DFS), in atypical meningiomas. p-mTOR immunohistochemical expression was analyzed in 48 atypical meningiomas and correlated with clinicopathological parameters and with DFS. Eighty-one percent of atypical meningiomas expressed p-mTOR Ser2448. High immuno-expression was significantly associated with recurrences (P = 0.01) and lower DFS (P = 0.01). The presence of brain invasion, high mitotic index plus sheeting, and Simpson grade were significant and independent prognostic variables at multivariate analysis. p-mTOR Ser2448 is expressed in atypical meningiomas. High expression predicts development of recurrences and shorter DFS in patients affected by these tumors. Since p-mTOR Ser2448 is a target of anti-neoplastic drugs, evaluation of its expression may be used, not only to identify atypical meningiomas at higher risk of recurrence, but also to select those to submit to adjuvant targeted chemotherapy.

Glioblastoma with tumor-to-tumor metastasis from lung adenocarcinoma.

Glioblastoma is a tumor with widely variable morphology. It may rarely show pseudoepithelial components or true epithelial differentiation. Metastasis to glioblastomas have been previously reported, but were unsupported by immunohistochemical or molecular analyses. Herein we describe a glioblastoma with carcinomatous foci in a patient with no past clinical history of tumors outside the central nervous system. The carcinomatous foci expressed epithelial, but not glial markers. Therefore, whole-body imaging was carried out to verify the presence of carcinoma. A lung mass was biopsied and it resulted as primary lung adenocarcinoma. Carcinomatous foci of glioblastoma and lung adenocarcinoma had the same KRAS mutation which was absent in glial areas of the glioblastoma. Thus, glioblastoma with tumor-to-tumor metastasis was diagnosed. This case demonstrates that, albeit rare, metastases to glioblastoma may occur, and they should be considered in the differential diagnosis of glioblastoma with carcinomatous foci. Even when the past clinical history is negative, the presence of carcinoma should be investigated to rule out glioblastoma with tumor-to-tumor metastasis.

Extra-axial anaplastic astroblastoma in a 67-year-old woman.

Astroblastoma is a rare glial neoplasia of the central nervous system. It is histologically defined by the presence of neoplastic cells with non- or slightly tapering processes arranged around blood vessels (astroblastic rosettes) and conventionally subdivided into well-differentiated and anaplastic. It commonly affects children and young adults, although cases and due to its superficial location in the brain cortex, it can mimic an extra-axial mass on magnetic resonance imagining. Herein, we describe a unique case of pure extra-axial anaplastic astroblastoma in an elderly woman. Awareness that astroblastoma may be also extra-axial and affect older subjects, may be helpful for its identification and differential diagnosis toward more common entities at this site and age of onset, and for appropriate therapeutic management as well.

Poorly differentiated clusters (PDC) in colorectal cancer: Does their localization in tumor matter?

Poorly differentiated clusters (PDC) are aggregates of at least five neoplastic cells lacking evidence of glandular differentiation. By definition, they can be present at the invasive front (peripheral PDC or pPDC) and within the tumor stroma (central PDC or cPDC). In colorectal cancer (CRC), PDC are considered adverse prognosticators and seem to reflect epithelial mesenchymal transition (EMT). In this study, we have investigated the immuno-expression of two EMT-related proteins, E-cadherin and ß-catenin, in PDC of primary CRCs and matched liver metastases. pPDC always showed nuclear ß-catenin staining and diffusely reduced/absence of E-cadherin expression as opposed cPDC which showed nuclear ß-catenin immunoreactivity and E-cadherin expression in about 50% of cases. In addition, the pattern of ß-catenin and E-cadherin expression differed between PDC and the main tumor, and between primary CRC and liver metastasis (LM), in a percentage of cases. A discordant pattern of ß-catenin and E-cadherin expression between pPDC and cPDC, between main tumor and cPDC, and between primary CRC and LM, confirms that EMT is a dynamic and reversible process in CRC. On the overall, this suggests that pPDC and cPDC are biologically different. We may advocate that PDC develop at the tumor center (cPDC) and then some of them migrate towards the tumor periphery while progressively completing EMT process (pPDC). Based on these results, PDC presence and counting may have different prognostic relevance if the assessment is done at the invasive front of the tumor or in the intratumor stroma.

Pituitary atypical teratoid rhabdoid tumor in a patient with prolactinoma: A unique description.

Atypical teratoid rhabdoid tumor (ATRT) is an aggressive tumor of the CNS and characteristically occurs in the pediatric age. In adulthood, ATRT is rare and it is mainly localized in the cerebral hemispheres. Only 16 cases of ATRT have been described in the sellar region up to now. Interestingly, all sellar ATRTs occurred in adult female patients. Herein we report a novel case of sellar ATRT in a patient with previous history of lactotroph adenoma. Similar to other sellar ATRTs, this case occurred in a female adult patient. At histological examination, it was characterized by a small number of rhabdoid cells. In addition, it did not have homozygous deletion of SMARCB1 gene, but it rather showed a frameshift mutation at exon 4 of SMARCB1 which had not been previously found in ATRT. Clinico-pathological and molecular findings observed in this case confirm previous evidence that sellar ATRT seems to be a distinct entity. Association with previous prolactin-secreting pituitary adenoma is discussed.

Histological grading based on poorly differentiated clusters is predictive of tumour response and clinical outcome in rectal carcinoma treated with neoadjuvant chemoradiotherapy.

AIMS: The clinical outcome of patients with locally advanced rectal cancer who undergo neoadjuvant chemoradiotherapy (CRT) is influenced by the tumour response to treatment, which is reflected by tumour regression grade and post-treatment (y) TNM stage. Little is known about the prognostic value of pretreatment histopathological features of the tumour that may be useful to discriminate potential non-responders and to design tailored therapeutic strategies. In this study, we aimed to investigate the prognostic role of poorly differentiated clusters (PDCs) of neoplastic cells in pretreatment biopsies of patients with rectal cancer treated with neoadjuvant CRT. METHODS AND RESULTS: Grading based on PDC counting was retrospectively applied to 204 pretreatment endoscopic biopsies of rectal carcinomas from patients treated with neoadjuvant CRT and surgery. Interobserver agreement in the assessment of PDC grade was good. High PDC grade was significantly associated with high yT stage (P = 0.044), yM+ status (P = 0.0004), and unchanged TNM stage or TNM upstaging (P = 0.032). In addition, high PDC grade was a significant and independent prognostic factor for cancer-specific survival. CONCLUSIONS: PDC grade may be assessed in preoperative biopsies of rectal cancer with good reproducibility. High PDC grade in a pretreatment tumour is significantly associated with a poor response to therapy. Hence, we suggest that PDC grading might be used as a significant predictive and prognostic factor in patients with locally advanced rectal cancer who are treated with neoadjuvant CRT, and to identify high-risk patients who need surgery and adjuvant chemotherapy.

Cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal neoplasms occurring in the gastrointestinal tract.

The purpose of the present review is to analyze the cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal gastrointestinal neoplams (MGNs), a group of unusual neoplastic conditions with different biological behavior. These tumors exhibit clinical pictures strictly related to the site of origin and dimensions, even if they appear generally with an intramural localization. This latter point may suggest an useful application of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), mainly followed by the cell-block procedure (CBP) in the differential diagnostic approach. First of all, we discuss the most common entity of MGNs represented by gastrointestinal stromal tumors (GISTs), analyzing the morphologic characteristics and stressing the strength of immunohistochemical algorithm for diagnostic purposes. Successively, we have reported the less common group of spindle-shaped MGNs comprehensive of those arising elsewhere the soft tissues, such as leiomyomas, leiomyosarcomas, schwannomas, inflammatory myofibroblastic tumor and intra-abdominal desmoid fibromatosis. Finally, very uncommon spindle-shaped MGNs, like clear cell, follicular dendritic cell, undifferentiated pleomorphic and radiation-induced sarcomas as well as spindle cell dedifferentiated liposarcomas, have been briefly mentioned.

Cystic endosalpingiosis of lumbar nerve root: a unique presentation.

AIMS: Endosalpingiosis is a non-neoplastic condition characterized by the presence of ciliated epithelium, resembling tubal epithelium, in heterotopic locations. Its presence has been reported in several anatomical sites in the pelvic, abdominal, and thoracic cavities. Herein we report a rare case of endosalpingiosis presenting as a cystic mass with spinal nerve root attachment. METHODS: Clinical history was obtained through review of medical records. The surgical specimen was formalin fixed and paraffin embedded for histological evaluation with hematoxylin and eosin stain and immunohistochemistry. RESULTS: The patient complained of worsening lumbar back pain that started several years before. Magnetic resonance imaging documented the presence of an intradural mass at L1 - 2. Histological appearance showed a cyst lined by a simple epithelium with ciliated, columnar, and intercalated cells, and immunohistochemistry was positive for keratins, EMA, estrogen, and progesterone receptors, PAX8 and WT1. GFAP and S100 were negative. Ki67 labeling index was low. CONCLUSION: Endosalpingiosis may rarely involve lumbar nerve roots and must be distinguished from a variety of more common cysts and neoplasms. In view of its potential for neoplastic transformation, recognition of endosalpingiosis may be important in cases with incomplete surgical resection.
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