Proper Tweeting Etiquette Guidelines for Pathologists, Trainees, and Medical Students on #PathTwitter.

The use of social media in pathology has broadly had a positive impact on pathology education and outreach with the frequent posting of high-quality educational material of potential value to trainees, practicing pathologists, and other clinical and laboratory specialists. These posts are also of potential utility and interest to members of the public, who are now more than ever able to gain a window into the field and the role of pathologists in their medical care. There can be a lighthearted aspect to teaching material with the use of food items/analogies, emojis, or other descriptors, which may cross over into the classroom. However, when pathology discussion is taken to a public forum, such as on Twitter (parent company: X Corp.), there is the potential for posted material to be misunderstood, such as when certain emojis or adjectives may be used to describe a human disease state or patient sample. The authors present examples of potential areas of caution, suggestions of how to create a positive impact, and brief guidelines for social media etiquette on #PathTwitter that may apply to other social media platforms widely used by pathologists (including, but not limited to, Facebook, Instagram, YouTube, and KiKo). While the points discussed here may be common knowledge and well-known to pathologists who use social media for virtual medical education, the concerns mentioned here (such as using language like "beautiful" to describe abnormal mitotic figures and cancer cells) still exist and, henceforth, bear reinforcing.

#PathX: #PathTwitter's Transformation and a Discussion on Different Social Media Platforms Used by Pathologists in 2024.

#PathTwitter is a well-known virtual community that has historically been positive for pathologists, trainees, and medical students worldwide to communicate, collaborate, and connect for free. However, in 2023, the popular social media platform Twitter (parent company: X Corp.) transitioned to "X" and, with this, #PathTwitter evolved into #PathX. Although the overall user experience of X and Twitter has not changed significantly, this transition brought much anecdotal hesitancy from the online virtual pathology community early on. Thus, the purpose of this review is to discuss the background of Twitter's importance in pathology, the implications of this transition to the online pathology community, current views from this community regarding Twitter versus X, and to provide an overview of pertinent changes in the platform, as well as of different popular social media platforms that may be used by pathologists in 2024.

TLE3 Sustains Luminal Breast Cancer Lineage Fidelity to Suppress Metastasis.

Breast cancer subtypes and their phenotypes parallel different stages of the mammary epithelial cell developmental hierarchy. Discovering mechanisms that control lineage identity could provide novel avenues for mitigating disease progression. Here we report that the transcriptional corepressor TLE3 is a guardian of luminal cell fate in breast cancer and operates independently of the estrogen receptor. In luminal breast cancer, TLE3 actively repressed the gene-expression signature associated with highly aggressive basal-like breast cancers (BLBC). Moreover, maintenance of the luminal lineage depended on the appropriate localization of TLE3 to its transcriptional targets, a process mediated by interactions with FOXA1. By repressing genes that drive BLBC phenotypes, including SOX9 and TGFß2, TLE3 prevented the acquisition of a hybrid epithelial-mesenchymal state and reduced metastatic capacity and aggressive cellular behaviors. These results establish TLE3 as an essential transcriptional repressor that sustains the more differentiated and less metastatic nature of luminal breast cancers. Approaches to induce TLE3 expression could promote the acquisition of less aggressive, more treatable disease states to extend patient survival. SIGNIFICANCE: Transcriptional corepressor TLE3 actively suppresses SOX9 and TGFß transcriptional programs to sustain the luminal lineage identity of breast cancer cells and to inhibit metastatic progression.

Focal Adhesion Kinase Provides a Collateral Vulnerability That Can Be Leveraged to Improve mTORC1 Inhibitor Efficacy.

The PI3K/AKT/mTORC1 pathway is a major therapeutic target for many cancers, particularly breast cancer. Everolimus is an mTORC1 inhibitor used in metastatic estrogen receptor-positive (ER+) and epidermal growth factor receptor 2-negative (HER2-) breast cancer. However, mTORC1 inhibitors have limited efficacy in other breast cancer subtypes. We sought to discover collateral sensitivities to mTORC1 inhibition that could be exploited to improve therapeutic response. Using a mouse model of breast cancer that is intrinsically resistant to mTORC1 inhibition, we found that rapamycin alters the expression of numerous extracellular matrix genes, suggesting a potential role for integrins/FAK in controlling mTORC1-inhibitor efficacy. FAK activation was also inversely correlated with rapamycin response in breast cancer cell lines. Supporting its potential utility in patients, FAK activation was observed in >50% of human breast cancers. While blocking FAK in mouse models of breast cancer that are highly responsive to rapamycin had no impact on tumor growth, FAK inhibition sensitized rapamycin-resistant tumors to mTORC1 inhibition. These data reveal an innate dependency on FAK when mTORC1 signaling is lost in tumors that are resistant to mTORC1 inhibitors. They also suggest a precision medicine approach to improving mTORC1 inhibitor efficacy in resistant cancers by suppressing FAK signaling.

P16 Expression in Primary Vulvar Extramammary Paget Disease.

P16 immunohistochemistry has been widely used in facilitating the diagnosis of human papillomavirus (HPV)-related usual type vulvar intraepithelial neoplasm. However, studies of p16 expression in primary vulvar extramammary Paget disease (EMPD) are limited. We assessed the p16 expression by immunohistochemistry in 40 cases of primary vulvar EMPD, including 34 cases of intraepithelial vulvar EMPD and 6 cases of invasive vulvar EMPD and correlated p16 expression patterns with disease progression. Overall, p16 expression was present in 36 cases (90%), including 20 cases (50%) with focal staining pattern and 16 cases (40%) with diffuse staining pattern. All 20 cases with focal p16 staining pattern were intraepithelial vulvar EMPD. Diffuse p16 staining pattern was present in 10/30 cases (33.3%) of intraepithelial EMPD and in 6/6 cases (100%) with invasive vulvar EMPD. Negative p16 staining was present in four intraepithelial EMPD cases. Using a highly sensitive RNA in situ hybridization method, we did not detect high-risk HPV in the selected 10 cases with diffuse p16 staining pattern, including 6 cases of intraepithelial EMPD and 4 cases of invasive EMPD. We also observed that intraepithelial EMPD had predominantly cytoplasmic p16 immunoreactivity, whereas nuclear p16 immunoreactivity was mainly seen in invasive EMPD components. Our study demonstrated that the p16 positive immunostaining was seen in the majority of primary vulvar EMPD which is not related to HPV infection. Therefore, knowing the overlapping p16 immunostaining patterns in vulvar EMPD and usual type vulvar intraepithelial neoplasm is important to render the correct diagnosis.

Significance of atypical endometrial cells in women younger than 40 years of age.

INTRODUCTION: The presence of atypical endometrial cells in the Papanicolaou (Pap) test has been associated with an increased rate of endometrial malignancy, with reported rates ranging from 14% to 47%. However, most reported studies have focused on patients who were aged >40 years. The purpose of the present study was to investigate the clinical significance of identifying atypical endometrial cells in Pap test samples in women aged <40 years of age. MATERIALS AND METHODS: A search of the cytology Pap test database was performed from 2000 to 2014 using the keywords "atypical endometrial cells" or "atypical glandular cells favor endometrial origin" in women aged <40 years. The available ThinPrep slides were reviewed. The patients' clinical presentation, follow-up endometrial biopsy findings, treatment, and clinical follow-up data were recorded. Endometrial carcinoma tissue sections were screened for Lynch syndrome. RESULTS: The database search yielded 63 study cases. Of these 63 patients, 52 had subsequently undergone endometrial biopsy. Of the 52 patients with follow-up biopsy findings available, 9 (17.3%) had premalignant (5 with atypical hyperplasia) or malignant (4 with endometrioid adenocarcinoma) lesions. In addition, 16 patients (30.8%) had other endometrial pathologic features. The 9 patients with premalignant or malignant endometrial lesions (8 white, 1 black) were overweight or obese; 3 of the patients did not have any clinical symptoms. All 4 patients with endometrioid adenocarcinoma had negative Lynch syndrome screening findings. CONCLUSIONS: Our results suggest that it is important to recognize the presence of atypical endometrial cells in the Pap tests from young patients, given its association with the finding of premalignant and malignant pathologic features in subsequent endometrial biopsies.

Uterine Inflammatory Myofibroblastic Tumor Showing an Atypical ALK Signal Pattern by FISH and DES-ALK Fusion by RNA Sequencing: A Case Report.

Inflammatory myofibroblastic tumors (IMTs) are spindle cell neoplasms of intermediate (borderline) biologic potential with tendency for local recurrence but low risk of metastasis. They affect children more than adults. The most common sites of involvement are the lung, soft tissue, peritoneum, bladder, and less commonly the gynecologic tract. IMTs are characterized by spindle to epithelioid cells with myofibroblastic differentiation, some degree of smooth muscle differentiation, myxoid stroma and usually associated with brisk lymphoplasmacytic infiltrates. In about half of the cases, IMTs are associated with rearrangements of the anaplastic lymphoma kinase (ALK) gene located at chromosome 2p23. The ALK rearrangement can be detected by immunohistochemistry for ALK protein expression (mostly cytoplasmic with or without perinuclear accentuation) or by fluorescent in situ hybridization (FISH) using dual-color break-apart probes for which the typical pattern is seen as split 3' end (red) and 5' end (green) probe signals in addition to single normal, unsplit red-green signal pair (yellow). Herein we describe a case of uterine IMT initially misdiagnosed intraoperatively as leiomyoma which showed sparse lymphocytic infiltrates, positive ALK expression by immunohistochemistry, a predominantly atypical FISH signal pattern (1 yellow and 1 red signal only) and few typical signal patterns (1 yellow, 1 red, and 1 green signal) in a smaller population of tumor cells. The RNA sequencing showed a recently described DES-ALK fusion transcript in the tumor cells, suggesting an intrachromosomal inversion and deletion as the likely underlying mechanism for the atypical FISH pattern. Familiarity with the unusual morphology and atypical FISH pattern is crucial given that this tumor has an activating ALK rearrangement and may benefit from targeted tyrosine kinase inhibitors in the future.

Thy-1 predicts poor prognosis and is associated with self-renewal in ovarian cancer.

BACKGROUND: Ovarian cancer is the leading cause of gynecologic cancer death in the United States despite effective first-line systemic chemotherapy. Cancer stem cells (CSCs) retain the ability to self-renew and proliferate and may be a means of harboring disease that evades standard treatment strategies. We previously performed a high-throughput screen to assess differential protein expression in ovarian CSCs compared to non-CSCs and observed that Thy-1 was more highly expressed in CSCs. Our primary aim was to validate Thy-1 (CD90) as a cancer stem cell (CSC) marker in epithelial ovarian cancer (EOC), correlate with clinical outcomes, and assess as a potential therapeutic target. RESULTS: Kaplan Meier (KM) Plotter data were correlated with survival outcomes. Quantitative real-time PCR, flow cytometry, and immunoblots assessed RNA and protein expression. Limiting dilution assays assessed self-renewal capacity and proliferation assays assessed proliferative capacity. RNA in-situ hybridization was performed on patient specimens to assess feasibility. Thy-1 (CD90) is more highly expressed in ovarian CSCs than non-CSCs, in EOC compared to benign ovarian epithelium (P < 0.001), and is highest in serous EOC (P < 0.05). Serous ovarian cancers with high Thy-1 expression have poorer outcomes (median PFS 15.8 vs. 18.3 months, P = 0 < 0.001; median OS 40.1 v. 45.8 months, P = 0.036). Endometrioid ovarian cancers with high Thy-1 have poorer PFS, but no difference in OS (upper quartile PFS 34 v. 11 months, P = 0.013; quartile OS not reached, P = 0.69). In vitro, Thy-1 expression is higher in CSCs versus non-CSCs. EOC cells with high Thy-1 expression demonstrate increased proliferation and self-renewal. Thy-1 knockdown in EOC cells decreases proliferative capacity and self-renewal capacity, and knockdown is associated with decreased expression of stem cell transcription factors NANOG and SOX2. RNA in situ hybridization is feasible in ovarian cancer tissue specimens. CONCLUSIONS: Thy-1 is a marker of ovarian CSCs. Increased expression of Thy-1 in EOC predicts poor prognosis and is associated with increased proliferative and self-renewal capacity. Thy-1 knockdown decreases proliferative and self-renewal capacity, and represents a potential therapeutic target.

Role of ThinPrep liquid-based cytology in evaluation of the endocervical canal in patients with abnormal cervical screening.

INTRODUCTION: Endocervical sampling is frequently used as an adjunct to colposcopy. Few studies address the role of endocervical brushing (ECB) with liquid-based cytology (LBC) for evaluation of the endocervical canal. We assessed the roles of ThinPrep (TP) LBC of ECB specimens and cell blocks (CBs). MATERIALS AND METHODS: Pathology archives were searched for ECB specimens from 2010-2015. Preceding Papanicolaou test interpretation, human papillomavirus status, concurrent and follow-up surgical specimens, and ECB diagnoses were recorded. CB cellularity, when available, was scored on a scale of 0 to 4. The cellularity of the TP and CBs was compared. RESULTS: Of 365 ECB cases, 6 (1.6%) were insufficient for diagnosis, compared with a 5% rate for endocervical curettings. Eleven ECB cases (3%) showed low cellularity. Of the 241 (66%) cases with concurrent biopsies, the ECB diagnosis agreed with the biopsy diagnosis (within 1 grade) in 198 (82%) cases. In 9 (2.5%) cases, ECB was the only means of diagnosis of a high-grade squamous intraepithelial lesion / adenocarcinoma in situ confirmed on follow-up. Compared with TP LBC, the CBs (performed in 84 [23%] of cases) were of greater cellularity in 30 (42%) and of equal cellularity in 17 (24%). None of the CBs showed an additional epithelial abnormality missed in TP LBC. CONCLUSIONS: TP LBC is capable of detecting endocervical epithelial abnormalities and may be used as a substitute for endocervical curettings. Performing a CB did not lead to detection of additional abnormalities, although it complemented TP findings and facilitates the performance of ancillary studies.

Thickened Endometrium in Postmenopausal Women With an Initial Biopsy of Limited, Benign, Surface Endometrium: Clinical Outcome and Subsequent Pathologic Diagnosis.

Endometrial biopsy or curetting is indicated for postmenopausal women with abnormal uterine bleeding and/or thickened endometrium. Often, endometrial biopsy or curetting yields limited benign surface endometrium, which may indicate insufficient sampling. This study addresses the clinical outcome and subsequent pathologic diagnoses in postmenopausal women who received this initial diagnosis. Among a total of 370 endometrial biopsy or curetting between 2012 and 2015, 192 (52%) were diagnosed as limited benign surface endometrial epithelium. The women ranged in age from 55 to 91 yr old. Their clinical presentations mainly included postmenopausal bleeding, pelvic pain, and enlarged uterus. Primarily because the initial report was interpreted as "benign," 108 (57%) had no subsequent follow-up. Interestingly, women with an increased endometrial thickness were more likely to receive repeat evaluation. Among the 84 women who underwent follow-up endometrial sampling, 6 (7%) had hyperplasia with atypia or malignancy, 21 (25%) had a repeat diagnosis of limited surface sample, 4 (5%) had insufficient materials, and 53 (63%) had other benign findings. Among the subset of women who did receive subsequent follow-up, endometrial atypia or malignancies are more likely found in those with increased body mass index. In conclusion, a slight majority of women with postmenopausal bleeding and/or thickened endometrium had an initial limited surface endometrial sample. Most had no subsequent endometrial sampling. Among those with subsequent follow-up, the majority had benign findings. The study highlights the inconsistencies in adequacy criteria for endometrial sampling and the lack of standardization of subsequent management.

Expression of LC3B and FIP200/Atg17 in brain metastases of breast cancer.

BACKGROUND: Macroautophagy/autophagy is considered to play key roles in tumor cell evasion of therapy and establishment of metastases in breast cancer. High expression of LC3, a residual autophagy marker, in primary breast tumors has been associated with metastatic disease and poor outcome. FIP200/Atg17, a multi-functional pro-survival molecule required for autophagy, has been implicated in brain metastases in experimental models. However, expression of these proteins has not been examined in brain metastases from patients with breast cancer. METHODS: In this retrospective study, specimens from 44 patients with brain metastases of infiltrating ductal carcinoma of the breast (IDC), unpaired samples from 52 patients with primary IDC (primary-BC) and 16 matched-paired samples were analyzed for LC3 puncta, expression of FIP200/Atg17, and p62 staining. RESULTS: LC3-puncta+ tumor cells and FIP200/Atg17 expression were detected in greater than 90% of brain metastases but there were considerable intra- and inter-tumor differences in expression levels. High numbers of LC3-puncta+ tumor cells in brain metastases correlated with a significantly shorter survival time in triple-negative breast cancer. FIP200/Atg17 protein levels were significantly higher in metastases that subsequently recurred following therapy. The percentages of LC3 puncta+ tumor cells and FIP200/Atg17 protein expression levels, but not mRNA levels, were significantly higher in metastases than primary-BC. Meta-analysis of gene expression datasets revealed a significant correlation between higher FIP200(RB1CC1)/Atg17 mRNA levels in primary-BC tumors and shorter disease-free survival. CONCLUSIONS: These results support assessments of precision medicine-guided targeting of autophagy in treatment of brain metastases in breast cancer patients.

Cytologic-Histologic Discrepancies in Pathology of the Uterine Cervix: Analysis of the Clinical and Pathologic Factors.

Cytologic-histologic correlation (CHC) represents a documented effort to obtain and compare, when available, gynecologic cytology reports with an interpretation of high-grade squamous intraepithelial lesion or malignancy, with the subsequent histopathology report, and to determine the possible cause of any discrepancy. The correlation is influenced by multiple closely interdependent clinical and pathologic factors. Many of these factors including the sensitivity and accuracy of colposcopy-directed biopsy, the diligence of the colposcopist, and the attributes of the cervical lesion represent "preanalytical" factors which can significantly affect the CHC outcome, but are often less emphasized during CHC process. The status of "gold standard" of cervical biopsy histology will be less "golden" if clinicians miss, during colposcopy, the lesion which had been flagged by cytology. CHC also serves as one of the important assurance tools to monitor and improve the pathology laboratory overall quality, and the ability of the pathologists to enhance their diagnostic interpretation. As pathologists, we should make every effort to improve on CHC, by applying systematic approaches, both in technical laboratory and interpretive diagnosis, which increase yield and reduce diagnostic discrepancies. The widespread use of Human Papilloma Virus testing and p16 immunohistochemistry have significantly enhanced diagnostic accuracy both in cytology and in histology. Herein, we review the intimate relationships and factors that may govern discrepancies between cytology, colposcopy-directed biopsies, and biopsies with subsequent Loop Electroexcision Procedure for cervical squamous intraepithelial lesions. Ultimately the projected risk for high-grade squamous intraepithelial lesion and cancer and the suggested management guidelines are directly tied in with effective CHC.

CD55 regulates self-renewal and cisplatin resistance in endometrioid tumors.

Effective targeting of cancer stem cells (CSCs) requires neutralization of self-renewal and chemoresistance, but these phenotypes are often regulated by distinct molecular mechanisms. Here we report the ability to target both of these phenotypes via CD55, an intrinsic cell surface complement inhibitor, which was identified in a comparative analysis between CSCs and non-CSCs in endometrioid cancer models. In this context, CD55 functions in a complement-independent manner and required lipid raft localization for CSC maintenance and cisplatin resistance. CD55 regulated self-renewal and core pluripotency genes via ROR2/JNK signaling and in parallel cisplatin resistance via lymphocyte-specific protein tyrosine kinase (LCK) signaling, which induced DNA repair genes. Targeting LCK signaling via saracatinib, an inhibitor currently undergoing clinical evaluation, sensitized chemoresistant cells to cisplatin. Collectively, our findings identify CD55 as a unique signaling node that drives self-renewal and therapeutic resistance through a bifurcating signaling axis and provides an opportunity to target both signaling pathways in endometrioid tumors.

Follistatin is a metastasis suppressor in a mouse model of HER2-positive breast cancer.

BACKGROUND: Follistatin (FST) is an intrinsic inhibitor of activin, a member of the transforming growth factor-ß superfamily of ligands. The prognostic value of FST and its family members, the follistatin-like (FSTL) proteins, have been studied in various cancers. However, these studies, as well as limited functional analyses of the FSTL proteins, have yielded conflicting results on the role of these proteins in disease progression. Furthermore, very few have been focused on FST itself. We assessed whether FST may be a suppressor of tumorigenesis and/or metastatic progression in breast cancer. METHODS: Using publicly available gene expression data, we examined the expression patterns of FST and INHBA, a subunit of activin, in normal and cancerous breast tissue and the prognostic value of FST in breast cancer metastases, recurrence-free survival, and overall survival. The functional effects of activin and FST on in vitro proliferation, migration, and invasion of breast cancer cells were also examined. FST overexpression in an autochthonous mouse model of breast cancer was then used to assess the in vivo impact of FST on metastatic progression. RESULTS: Examination of multiple breast cancer datasets revealed that FST expression is reduced in breast cancers compared with normal tissue and that low FST expression predicts increased metastasis and reduced overall survival. FST expression was also reduced in a mouse model of HER2/Neu-induced metastatic breast cancer. We found that FST blocks activin-induced breast epithelial cell migration in vitro, suggesting that its loss may promote breast cancer aggressiveness. To directly determine if FST restoration could inhibit metastatic progression, we transgenically expressed FST in the HER2/Neu model. Although FST had no impact on tumor initiation or growth, it completely blocked the formation of lung metastases. CONCLUSIONS: These data indicate that FST is a bona fide metastasis suppressor in this mouse model and support future efforts to develop an FST mimetic to suppress metastatic progression.

Interobserver agreement in the cytologic grading of atypia in neoplastic pancreatic mucinous cysts with the 2-tiered approach.

BACKGROUND: The accurate cytologic grading of epithelial atypia in fine-needle aspirates of pancreatic mucinous cysts has important implications for clinical management. The Papanicolaou Society of Cytopathology has recommended a 2-tiered system of low-grade (LG) and high-grade (HG) for grading this atypia. Using this approach, this study examined the interobserver agreement within a group of cytopathologists at the Cleveland Clinic. METHODS: Twenty cases of fine-needle aspiration of pancreatic neoplastic mucinous cysts with documented histologic follow-up and representative lesional cells were selected. Blinded to the histologic outcome, 4 cytopathologists were independently asked to assign the highest grade of atypia with the 2-tiered system of LG and HG atypia for these cases. The interobserver agreement was calculated with the κ statistic. RESULTS: The overall raw agreement in the grading of atypia was 60%. The overall chance-adjusted agreement was fair (κ = 0.28). On the basis of the histologic outcomes, the cases were stratified into group A (HG dysplasia or worse) and group B (LG or intermediate-grade [IG] dysplasia on follow-up). Group A (n = 12) showed good chance-adjusted agreement (κ = 0.65). For group B, the chance-adjusted agreement among the observers was poor (κ = 0.03). CONCLUSIONS: This study shows that the cytologic recognition of HG dysplasia or worse as HG atypia in pancreatic mucinous cysts has a good degree of interobserver reproducibility among cytopathologists. In contrast, a problematic area with a lack of agreement appears to be the cytologic recognition of LG and IG dysplasia as LG atypia. Additional studies with the development of reproducible criteria and educational tools may help with this challenging distinction. Cancer Cytopathol 2016;124:909-916. © 2016 American Cancer Society.

The utility of repeated cytologic evaluation of cerebrospinal fluid in individuals with metastatic breast cancer.

INTRODUCTION: Metastasis of breast cancer to the central nervous system, either in the brain parenchyma or leptomeninges (LMC), is a late feature of the disease . Detection of malignant cells in the cerebrospinal fluid (CSF) is the diagnostic standard for LMC. Repeated CSF examinations are often performed following an initial diagnosis positive for malignancy. This study evaluates the significance of repeated CSF evaluation in women with metastatic breast cancer to the central nervous system. MATERIALS AND METHODS: Cases of adenocarcinoma of breast diagnosed by CSF cytology from 1990 through 2012 documenting: age, radiologic findings, treatment modality, and the number of repeated CSF cytology specimens and their respective interpretations. RESULTS: Fifty-one patients were identified; 28 patients (54.9%) had a single initial positive CSF performed and 23 (45.1%) had multiple CSF cytology samples (range = 2-25, mean = 5.5). Despite interval "negative" and "atypical cells" results on CSF cytology specimens, all 23 patients with multiple samples had at least one follow-up positive CSF cytology sample. CONCLUSION: The prognosis of the patients with an initial CSF diagnosis of adenocarcinoma was poor, regardless of the respective interpretations on the repeated CSF specimens, even in the presence of interval negative CSF.

Cytologic categorization of pancreatic neoplastic mucinous cysts with an assessment of the risk of malignancy: A retrospective study based on the Papanicolaou Society of Cytopathology guidelines.

BACKGROUND: Cytology plays a pivotal role in the preoperative diagnosis of pancreatic cysts. Here the Papanicolaou Society of Cytopathology (Pap Society) guidelines were used to reclassify and assess the malignancy risk of cytology diagnoses of histologically proven pancreatic neoplastic mucinous cysts. METHODS: A database search (January 2000 to June 2014) was performed for pancreatic neoplastic mucinous cyst resections with endoscopic ultrasound-guided fine-needle aspiration within the preceding year. Histologic diagnoses were reclassified according to the 2010 Word Health Organization criteria. For atypical/suspicious/positive cytology diagnoses, the cytology slides were reviewed, blinded to the histologic diagnoses. The cysts were reclassified according to the Pap Society guidelines, and the findings were correlated with the histology. RESULTS: One hundred thirty-eight cases of pancreatic neoplastic mucinous cysts were retrieved. Eleven cases with atypical/suspicious cytology diagnoses with unavailable slides were excluded. The remaining 127 cases included 81 intraductal papillary mucinous neoplasms and 46 mucinous cystic neoplasms. The sensitivity of cytology for the diagnosis of neoplastic mucinous cysts was 76.4%. The sensitivity, specificity, and accuracy of cytology for the diagnosis of malignancy (high-grade dysplasia or worse) were 48.3%, 94.9%, and 84.3%, respectively. The risk of malignancy was 17.4% for the nondiagnostic category, 0% for the negative category, 13% for the neoplastic category, 63.6% for the atypical category, 80% for the suspicious category, and 100% for a positive diagnosis. CONCLUSIONS: This study reveals that the Pap Society guidelines allow the accurate categorization of pancreatic neoplastic mucinous cysts with cytology. The diagnostic categories (from negative to positive) are associated with an increasing risk of malignancy, and this can further aid in patient management and risk stratification.

Abrupt loss of MLH1 and PMS2 expression in endometrial carcinoma: molecular and morphologic analysis of 6 cases.

Given that endometrial cancer (EC) is often the sentinel cancer for female Lynch syndrome patients, we have successfully implemented universal screening of ECs and have previously shown that this is the preferred method to identify these patients. However, during the course of universal screening of EC, we encountered 6 cases with an unusual pattern of mismatch-repair protein immunohistochemistry that has not been previously described in this setting. In these 6 cases, there was an abrupt loss of MLH1 and PMS2 expression in a portion of the tumor. In 3 cases, marked histologic differences were identified between the areas of the tumor with retained expression and areas with loss of expression. In 2 cases, the areas with loss of expression were of higher grade (1 demonstrated solid growth and the other demonstrated increased nuclear atypia with diffuse p53 expression). In 4 tumors, histologic features associated with microsatellite instability (MSI) were present, including increased intraepithelial lymphocytes. The areas with loss of and retained MLH1/PMS2 expression were separately microdissected and assessed for MSI and MLH1 promoter methylation. The areas with loss of MLH1 and PMS2 more commonly demonstrated MSI compared with the areas with intact expression (83% vs. 33%). MLH1 promoter methylation analysis demonstrated heterogenous hypermethylation, as all areas with loss of MLH1/PMS2 expression had more extensive methylation of MLH1 compared with those areas with retained expression. In summary, we describe the histologic and molecular features of 6 cases of EC with abrupt loss of MLH1 and PMS2 expression and demonstrate that heterogenous methylation of the MLH1 promoter results in this distinct and unusual pattern of immunohistochemical expression.

p16 Immunohistochemistry is useful in confirming high-grade squamous intraepithelial lesions (HSIL) in women with negative HPV testing.

SUMMARY: It is believed that almost all squamous cell carcinomas of the cervix are associated with HR-HPV infection. However, a subset of high-grade squamous intraepithelial lesion (HSIL) (CIN2 and CIN3) lesions is found in those women with negative HPV testing. Knowledge of HPV status can influence pathologists' decision in rendering the diagnosis of cervical squamous intraepithelial lesions (SIL). p16, a surrogate marker for HSIL, has been widely applied to facilitate accurate diagnosis of HPV-related cervical dysplasia, especially CIN2 and CIN3. To assess whether p16 immunostaining is useful in diagnosing HSIL in women with negative HPV testing, we studied the utility of p16 immunohistochemistry in 46 women of HSIL and HPV-negative status. A total of 46 cases of initial biopsies with histopathologically diagnosed HSIL (CIN2 and CIN3) were identified from our hospital archives. All women were HPV negative with at least 1 HPV testing using HC-II (Qiagen) within 6 mo of initial biopsy. LEEP procedures within 6 mo of initial biopsies were reviewed and documented. Immunohistochemical staining of p16 was performed on recuts of all original biopsies. Some LEEP specimens without evidence of HSIL (CIN2 and CIN3) on hematoxylin and eosin had recuts with deeper levels and p16 immunostaining to confirm the negative diagnosis. p16 immunostaining were evaluated as negative, focal/patchy, or diffuse staining pattern. Patients' HPV testing status and related clinicopathologic information were reviewed, tabulated, and correlated with p16 immunostaining patterns. Forty-six women between the age of 17 and 58 yr, with a median of 35 yr, were all HPV-negative. All women, except 2, had an abnormal cytologic interpretation at the time of HPV testing ranging from ASC-US to HSIL. Forty-two women (91.3%) had LEEP procedures done within 6 mo of the initial biopsies. LEEP specimens showed that 76.2% (32 cases) women had HSIL, including 22 cases of CIN2 and 10 cases of CIN3, 14.3% (6 cases) had low-grade squamous intraepithelial lesion (CIN1), and 9.5% (4 cases) had benign cervix. p16 immunostaining, performed on initial biopsies with histopathologic diagnoses of CIN2 or CIN3, showed that 66.7% (28 cases) had diffuse staining pattern, 16.7% (7 cases) had focal/patchy pattern, and 16.7% (7 cases) had negative p16 staining. On LEEP follow-up, all 28 cases with diffuse p16 staining pattern had HSIL (CIN2 and CIN3), and all 7 cases with negative p16 staining had no detectable high-grade dysplasia. For those 7 cases with focal/patch p16 staining pattern, 4 had HSIL (CIN2) and 3 had low-grade squamous intraepithelial lesion (CIN1) on LEEP follow-up. Approximately 76% of women with negative HPV and diagnosis of HSIL (CIN2 and CIN3) on initial biopsy had confirmed HSIL (CIN2 and CIN3) in subsequent LEEP follow-up. Diffuse p16 immunostaining pattern is the hallmark of HSIL because it correlates 100% with CIN2 and CIN3 lesions between initial biopsy and LEEP specimens, regardless of the HPV status. The negative predictive value for p16 immunoreactivity to predict cervical lesions less than high grade is almost 100% in our study. Our study suggests that when a woman is negative for HPV and also negative for p16, diagnosis of HSIL should be very cautious in void of unnecessary LEEP procedures.

Endobronchial ultrasonography-guided transbronchial needle aspiration, an effective modality for sampling targeted thoracic lesions in adult lung transplant recipients.

INTRODUCTION: Lung transplantation (LTx) is performed for end-stage lung diseases that would be otherwise fatal. Pulmonary allograft recipients are a unique patient population as they are at high risk for malignancy and infectious complications due to the need for immunosuppression. Endobronchial ultrasonography (EBUS)-guided fine-needle aspiration (FNA) is a minimally invasive technique for evaluating abnormalities of the mediastinum/lungs. To our knowledge, this report is the first in the literature addressing targeted EBUS-FNA biopsies in patients who have undergone LTx. MATERIAL AND METHODS: During 5 years from May 1, 2009 to May 1, 2014, 582 patients underwent LTx at the Cleveland Clinic. A review of records indicated that 14 of these patients later underwent EBUS-FNA. Demographic and diagnostic parameters were recorded. RESULTS: A total of 14 patients (mean age 64 years) underwent EBUS-FNA after LTx. The mean interval between LTx and EBUS-FNA was 15 months. EBUS-FNA yielded cytologic material diagnostic of malignancy in 10 patients (71%) with one-half of those cases being squamous carcinomas. CONCLUSIONS: EBUS-FNA is a useful diagnostic modality in lung allograft recipients and is of value in confirming and staging thoracic malignancies in this population. Carcinoma subtyping is feasible by EBUS-FNA, and performance of ancillary studies to confirm clonality in post-transplant lymphoproliferative disorders is possible.