Evaluation of dual p16/Ki-67 immunostaining on anal cytology specimens.

INTRODUCTION: Dual immunostaining for p16/Ki67 is FDA-approved for use on liquid-based cervical cytology specimens; however, the utility of dual staining in anal cytology especially for ASCUS risk stratification is not well established. METHODS: We investigated dual staining performance on anal cytology specimens and correlated with subsequent cytologic interpretation, high-risk HPV status, and anal biopsy results. Dual staining for p16/Ki-67 was performed on all liquid-based anal cytology specimens from December 2021 to June 2022 (n = 43). RESULTS: Three patients had high grade squamous intraepithelial lesion (HSIL/AIN2-3) on biopsy; dual staining was positive in all three cases. All HR-HPV negative cases were negative for dual staining. Among the 12 ASCUS samples with subsequent anal biopsy results all also had HR-HPV testing. Due to small sample size of cases with squamous intraepithelial lesion (SIL) diagnosed on biopsy, the sensitivity and positive predictive value was not calculated. However, the specificity and negative predictive value of p16/Ki-67 dual staining for SIL of any grade on biopsy were 1 (95% CI: 0.66-1) and 0.9 (95% CI: 0.65-0.97) respectively, whereas the specificity and negative predictive value of HR-HPV testing for SIL of any grade on biopsy were 0.44 (95% CI: 0.14-0.79) and 0.8 (95% CI: 0.41-0.96) respectively. CONCLUSION: Dual p16/Ki-67 staining indicates transforming HPV infection and could help serve as an ancillary test for risk stratification for atypical anal cytology specimens. Among ASCUS samples, dual staining was specific for SIL of any grade with a high negative predictive value and therefore could be useful in clinical practices with limited availability for follow-up care.

Case of lung fine needle aspiration showing mucinous cells and extracellular mucin.

Mucinous neoplasm with extracellular mucin can be challenging to interpret on fine needle aspiration and core biopsies. Determining the biologic origin of the mucin/mucinous cells, that is, benign/incidental versus neoplasm, invasive versus in situ, and primary versus metastatic tumors, requires a thorough multidisciplinary evaluation. The work up of these lesions includes morphologic analysis with ancillary immunohistochemical and/or molecular studies and correlation with clinical and imaging studies. This review outlines a practical approach to the diagnosis of mucinous lesions in the lung with comprehensive review of literature.

HER2/ ERBB2 Immunohistochemical Expression and Copy Number Status in Ovarian Mucinous Tumors.

Primary mucinous ovarian carcinoma (MOC) is a rare ovarian epithelial cancer, which is often refractory to chemotherapy. HER2-targeting therapy is being increasingly considered in gynecologic malignancies. Although there have been limited studies examining the HER2 status of such tumors, the criteria for HER2 expression scoring have not been standardized for MOC as it has for other sites. This study aimed to survey immunohistochemical HER2 expression patterns in MOC and its precursor, mucinous borderline tumor in correlation with fluorescence in situ hybridization (FISH). Immunohistochemistry (IHC) for HER2 was performed on 12 cases of MOC and 15 mucinous borderline tumors, including 7 with intraepithelial carcinoma. HER2 expression was quantified using the gastric/gastroesophageal carcinoma protocol. Cases were considered 3+ if the tumor cells displayed strong complete or basolateral/lateral membranous staining in ≥10% of tumor cells. Cases (2+) had weak to moderate staining in ≥10% of tumor cells. Cases (1+) had faint staining in ≥10% of tumor cells. Cases considered 0 had no staining or faint staining in <10% of tumor cells. HER2 expression was also quantified with the endometrial serous carcinoma protocol, which uses a 30% tumor cell positivity cutoff. FISH for HER2 was performed on all 3+ and 2+ and a subset of 1+ cases. Of the MOC cases, 25% were 3+ and 1 mucinous borderline tumor with intraepithelial carcinoma had 3+ staining. All 3+ IHC MOC cases had >30% basolateral membranous staining. HER2 amplification was confirmed by FISH on all 3+ IHC cases and in one 2+ IHC case of MOC. Up to 25% of mucinous ovarian tumors showed HER2 IHC overexpression with an excellent correlation between IHC and FISH using the HER2 scoring protocol for either gastric/gastroesophageal carcinoma or uterine serous carcinoma.

Diagnostic utility of PRAME immunohistochemistry in PEComa family of tumors and morphologic mimics with emphasis on the gynecologic tract.

Perivascular epithelioid cell tumors (PEComas), rare mesenchymal tumors with myomelanocytic differentiation, can be a diagnostic challenge, often requiring a panel of immunohistochemical markers. Preferentially expressed antigen in melanoma (PRAME) is a relatively new antigen with utility in diagnosing melanomas. This study aimed to survey PRAME expression patterns in the PEComa family of tumors and morphologic mimics. Twenty cases of PEComas and 27 non-PEComas (10 leiomyosarcomas, 3 smooth muscle tumors of uncertain malignant potential [STUMPs], 11 leiomyomas, 1 uterine inflammatory myofibroblastic tumor [IMT], and 2 low-grade endometrial stromal sarcomas [LGESSs]) were stained with PRAME and compared to previously performed HMB45 and Melan-A stains, when available. Tumors showing no or barely perceptible PRAME staining at 10× were considered negative. Tumors were considered positive if there was full nuclear staining evident at 10× in at least one 10× field. Diffuse staining was defined as positivity in at least 80% of tumor nuclei. Overall, PRAME was expressed in 70% of PEComas, with diffuse positivity in 60%. However, PRAME was not specific for PEComas, with immunopositivity in the majority (70%) of uterine leiomyosarcoma cases, though negative in STUMP, leiomyoma, IMT, and LGESS cases. PRAME sensitivity was 70% and specificity was 74%, while HMB45 was more sensitive (90%) and specific (100%), but only 15% of PEComas showed diffuse staining. Melan-A staining was less common than HMB45 or PRAME, with only 18.8% sensitivity but 100% specificity. Among gynecologic PEComas, PRAME was expressed in 75% overall and enriched among malignant cases (85.7% positive). As part of an immunohistochemical panel, PRAME could be useful in the workup of PEComa cases. In the future, PRAME-specific immunotherapies may be beneficial in treating patients with malignant PEComas.

Investigation of discrepant mismatch repair immunohistochemistry and microsatellite instability polymerase chain reaction test results for gynecologic cancers using next-generation sequencing.

Gynecologic cancers are routinely screened for DNA mismatch repair (MMR) gene mutations using immunohistochemistry (IHC) and/or polymerase chain reaction (PCR) for microsatellite instability (MSI) to enable selection of immune checkpoint inhibitor therapy and screen for Lynch syndrome. The limited data that compare IHC and MSI in endometrial tumors have shown discordance rates of 5-10%. We reviewed MMR/MSI results in gynecologic cancers and used next-generation sequencing (NGS) to interrogate discrepancies. Of the 328 cases with both IHC and MSI results, 256 (78.0%) were microsatellite stable (MSS) with preserved MMR (pMMR), 64 (19.5%) cases were MSI-High (MSI-H) with MMR deficient (dMMR), 2 cases showed subclonal loss of MLH1 and PMS2 with MSI-H, and 6 cases were discordant. Overall, there was a 98.2% (322/328) IHC/MSI concordance. Discordant cases were retested and/or subject to NGS. Of the six discrepant cases, five showed dMMR with MSS and one showed pMMR with MSI-H. One dMMR/MSI-L case showed loss of PMS2 with a germline pathogenic mutation. The pMMR/MSI-H case was found to harbor pathogenic variants in MLH1 and MSH6. One of the two cases with subclonal populations demonstrated MSI-H in the dMMR area and MSS in the pMMR area. These results emphasize the importance of selecting the appropriate tumor tissue for both IHC and molecular testing and demonstrate that NGS can help resolve discrepant MMR and MSI results.

Value of additional sections: Tissue handling of small biopsies in detecting squamous dysplasia of the uterine cervix.

Cervical cancer screening is currently based on high-risk human papillomavirus (HR-HPV) molecular testing, Pap cytology testing, and histologic evaluation of cervical biopsies. As primary HPV screening for cervical cancer becomes widely used, some of the recommended screening guidelines propose colposcopy and biopsies following positivity for HPV16/18 without cytologic triage. In such instances, a biopsy would be the only tissue sample available for informing further management. The use of additional histologic levels on cervical biopsies is commonly employed to achieve a diagnosis, although no set criteria for when to obtain additional levels exist. In this study, we evaluated the value of additional sections in cervical biopsy and endocervical curetting, as well as clinical and histologic features that should be considered when ordering additional levels. Additional levels were obtained for the following scenarios: benign mucosa with Pap discrepancy (HSIL or ASC-H interpretation), size discrepancy with the gross description, suspicious atypia for a high-grade lesion, and long-standing high-risk HPV infection. A change in diagnosis was observed in 21.4% of the cases, with an upgrade to a high-grade squamous intraepithelial lesion (CIN2-3) in 12.1% of cases. An initial impression of atypia significantly correlated with both a change in diagnosis and an upgrade to CIN2-3. In the era of primary HPV screening, when evaluating tissue samples following positive HPV test, small, atypical foci should be followed by additional levels. We recommend six (6) initial levels on all cervical biopsies, particularly if there is no loss of tissue between the levels, to ensure an accurate interpretation. This will be crucial in the timely and accurate identification of HPV-related intraepithelial lesions and proper subsequent management.

Student-Authored Autopsy Reports of Anatomical Donors: Their First Patients.

The preparation of student-authored autopsy reports of anatomical donors was added to the Gross Anatomy course to integrate the basic and clinical sciences and determine whether students considered this early clinical exposure to be a valuable experience. All donors were scanned using computerized tomography (CT) and student groups received the scan of their donor and a report written by a radiologist. As students dissected, they took photographs and biopsies of pathological findings that were processed for microscopic evaluation. Following consultation with pathologists and radiologists, each group prepared an autopsy report that proposed a cause of death supported with macroscopic, microscopic, and CT images. Cardiovascular events and cancer were the most common. Autopsy reports were evaluated by the faculty and each student group received feedback with respect to content, accuracy, and completeness and whether faculty agreed with students' proposed cause of death. A majority of students answering an anonymous survey indicated that this exercise was valuable or somewhat valuable, but did not agree that preparation of the autopsy report resulted in their being more engaged during the course. Students agreed or somewhat agreed that the exercise should be repeated next year, that they gained insight into the clinical manifestations of disease, that they were able to interpret the CT scan themselves, that meeting with a pathologist was interesting, and that the time required to prepare the report was adequate. Since autopsy reports prepared by students are feasible and students found it to be a valuable experience, we suggest that medical schools add this to Gross Anatomy courses to introduce clinical material and increase clinical relevance.

Using electrospun poly(ethylene-oxide) nanofibers for improved retention and efficacy of bacteriolytic antibiotics.

The aim of this study was to demonstrate targeted delivery of protein-based bactericidal antibiotics using electrospun polymer nanofibers. Previous studies have utilized electrospinning to create nanofibers for the localized delivery of therapeutic agents, including non-steroidal anti-inflammatory drugs (NSAIDs) and low molecular weight heparin. By employing established electrospinning techniques, nanofibers of varying diameters (100-500 nm) were generated from a 0.05 % solution of poly(ethylene-oxide) (PEO) and the antimicrobial peptide, LL-37 was incorporated into the nanofiber meshwork. Initial experiments determined that the strong electric fields caused by electrospinning do not disrupt the antimicrobial properties of LL-37, thus justifying the application of LL-37 as an electrospun component. Disk diffusion assays and especially bacterial filtration studies with E. coli were conducted to quantify the drug delivery potential of the nanofibers. Disk diffusion revealed a small zone of inhibition of about 1 mm around the LL-37-incorporated nanofiber disk. Filtration tests demonstrated that electrospun PEO fibers were capable of delivering LL-37 consistently while still maintaining their antimicrobial abilities.