Virtual Staining of Nonfixed Tissue Histology.

Surgical pathology workflow involves multiple labor-intensive steps, such as tissue removal, fixation, embedding, sectioning, staining, and microscopic examination. This process is time-consuming and costly and requires skilled technicians. In certain clinical scenarios, such as intraoperative consultations, there is a need for faster histologic evaluation to provide real-time surgical guidance. Currently, frozen section techniques involving hematoxylin and eosin (H&E) staining are used for intraoperative pathology consultations. However, these techniques have limitations, including a turnaround time of 20 to 30 minutes, staining artifacts, and potential tissue loss, negatively impacting accurate diagnosis. To address these challenges, researchers are exploring alternative optical imaging modalities for rapid microscopic tissue imaging. These modalities differ in optical characteristics, tissue preparation requirements, imaging equipment, and output image quality and format. Some of these imaging methods have been combined with computational algorithms to generate H&E-like images, which could greatly facilitate their adoption by pathologists. Here, we provide a comprehensive, organ-specific review of the latest advancements in emerging imaging modalities applied to nonfixed human tissue. We focused on studies that generated H&E-like images evaluated by pathologists. By presenting up-to-date research progress and clinical utility, this review serves as a valuable resource for scholars and clinicians, covering some of the major technical developments in this rapidly evolving field. It also offers insights into the potential benefits and drawbacks of alternative imaging modalities and their implications for improving patient care.

Spatial transcriptomics and the anatomical pathologist: Molecular meets morphology.

In recent years anatomical pathology has been revolutionised by the incorporation of molecular findings into routine diagnostic practice, and in some diseases the presence of specific molecular alterations are now essential for diagnosis. Spatial transcriptomics describes a group of technologies that provide up to transcriptome-wide expression profiling while preserving the spatial origin of the data, with many of these technologies able to provide these data using a single tissue section. Spatial transcriptomics allows expression profiling of highly specific areas within a tissue section potentially to subcellular resolution, and allows correlation of expression data with morphology, tissue type and location relative to other structures. While largely still research laboratory-based, several spatial transcriptomics methods have now achieved compatibility with formalin-fixed paraffin-embedded tissue (FFPE), allowing their use in diagnostic tissue samples, and with further development potentially leading to their incorporation in routine anatomical pathology practice. This mini review provides an overview of spatial transcriptomics methods, with an emphasis on platforms compatible with FFPE tissue, approaches to assess the data and potential applications in anatomical pathology practice.

Tumour budding as a prognostic biomarker in biopsies and resections of neoadjuvant-treated rectal adenocarcinoma.

BACKGROUND: Tumour budding (TB) is a marker of tumour aggressiveness which, when measured in rectal cancer resection specimens, predicts worse outcomes and response to neoadjuvant therapy. We investigated the utility of TB assessment in the setting of neoadjuvant treatment. METHODS AND RESULTS: A single-centre, retrospective cohort study was conducted. TB was assessed using the hot-spot International Tumour Budding Consortium (ITBCC) method and classified by the revised ITBCC criteria. Haematoxylin and eosin (H&E) and AE1/AE3 cytokeratin (CK) stains for ITB (intratumoural budding) in biopsies with PTB (peritumoural budding) and ITB (intratumoural budding) in resection specimens were compared. Logistic regression assessed budding as predictors of lymph node metastasis (LNM). Cox regression and Kaplan-Meier analyses investigated their utility as a predictor of disease-free (DFS) and overall (OS) survival. A total of 146 patients were included; 91 were male (62.3%). Thirty-seven cases (25.3%) had ITB on H&E and 79 (54.1%) had ITB on CK assessment of biopsy tissue. In univariable analysis, H&E ITB [odds (OR) = 2.709, 95% confidence interval (CI) = 1.261-5.822, P = 0.011] and CK ITB (OR = 2.165, 95% CI = 1.076-4.357, P = 0.030) predicted LNM. Biopsy-assessed H&E ITB (OR = 2.749, 95% CI = 1.258-6.528, P = 0.022) was an independent predictor of LNM. In Kaplan-Meier analysis, ITB identified on biopsy was associated with worse OS (H&E, P = 0.003, CK: P = 0.009) and DFS (H&E, P = 0.012; CK, P = 0.045). In resection specimens, CK PTB was associated with worse OS (P = 0.047), and both CK PTB and ITB with worse DFS (PTB, P = 0.014; ITB: P = 0.019). In multivariable analysis H&E ITB predicted OS (HR = 2.930, 95% CI = 1.261-6.809) and DFS (HR = 2.072, 95% CI = 1.031-4.164). CK PTB grading on resection also independently predicted OS (HR = 3.417, 95% CI = 1.45-8.053, P = 0.005). CONCLUSION: Assessment of TB using H&E and CK may be feasible in rectal cancer biopsy and post-neoadjuvant therapy-treated resection specimens and is associated with LNM and worse survival outcomes. Future management strategies for rectal cancer might be tailored to incorporate these findings.

Role of sentinel lymph node evaluation during hysterectomy for preoperative pathology diagnosis of endometrial intraepithelial neoplasia in a community hospital setting.

OBJECTIVE: To determine the utility of sentinel lymph node (SLN) evaluation during hysterectomy for endometrial intraepithelial neoplasia (EIN) in a community hospital setting and identify descriptive trends among pathology reports from those diagnosed with endometrial cancer (EC). METHODS: We reviewed patients who underwent hysterectomy from January 2015 to July 2022 for a pathologically confirmed diagnosis of EIN obtained by endometrial biopsy (EMB) or dilation and curettage. Data was obtained via detailed chart review. Statistical testing was utilized for between-group comparisons and multivariate logistic regression modeling. RESULTS: Of the 177 patients with EIN who underwent hysterectomy during the study period, 105 (59.3%) had a final diagnosis of EC. At least stage IB disease was found in 29 of these patients who then underwent adjuvant therapy. Pathology report descriptors suspicious for cancer and initial specimen type obtained by EMB were independently and significantly associated with increased odds of EC diagnosis (aOR 8.192, p < 0.001;3.746, p < 0.001, respectively). Operative times were not increased by performance of SLN sampling while frozen specimen evaluation added an average of 28 min to procedure length. Short-term surgical outcomes were also similar between groups. CONCLUSION: Patients treated for EIN at community-based institutions might be more likely to upstage preoperative EIN diagnoses and have an increased risk of later stage disease than previous research suggests. Given no surgical time or short-term outcome differences, SLN evaluation should be more strongly considered in this practice setting, especially for patients diagnosed by EMB or with pathology reports indicating suspicion for EC.

Abnormal bone marrow findings in patients following treatment with chimeric antigen receptor-T cell therapy.

BACKGROUND: Bone marrow (BM) assessment after CAR-T cell immunotherapy infusion is not routinely performed to monitor adverse events such as cytopenias, hemophagocytic lymphohistiocytosis, or infections. Our institution has performed BM biopsies as part of CAR-T cell treatment protocols, encompassing pre- and post-treatment time points and during long-term follow-up. METHODS: We conducted a systematic retrospective review of BM abnormalities observed in samples from 259 patients following CAR-T cell immunotherapy. We correlated BM pathology findings with mortality, relapse/residual disease, and laboratory values. RESULTS: At a median of 35.5 days post-CAR-T infusion, 25.5% showed severe marrow hypocellularity, and 6.2% showed serous atrophy, and peripheral blood cytopenias corroborated these observations. Marrow features associated with reduced disease burden post-CAR-T infusion include increased lymphocytes seen in 16 patients and an increase of macrophages or granulomatous response seen in 25 patients. However, a 100-day landmark analysis also showed increased marrow histiocytes were associated with lower survival (median OS 6.0 vs. 21.4 months, p = .026), as was grade 2-3 marrow reticulin (18 patients) (median OS 12.5 vs. 24.2 months, p = .034). CONCLUSIONS: These data represent the first systematic observations of BM changes in patients receiving CAR-T cell immunotherapy.

Index tumor location affected early biochemical recurrence after radical prostatectomy in patients with negative surgical margin: a retrospective study.

BACKGROUND: Index tumors are the most aggressive tumors of the prostate. However, their clinical significance remains unclear. This study aimed to assess the incidence of index tumor location according to the zonal origin and whether these locations affect the prognosis after radical prostatectomy in patients with negative surgical margins. METHODS: This single-centered, retrospective study evaluated 1,109 consecutive patients who underwent radical prostatectomies. An index tumor was defined as the largest tumor in the prostate gland. We detected these locations based on McNeal's zonal origin using whole-mount sections. Biochemical recurrence (BCR) free survival curves were generated using the Kaplan-Meier method. Univariate and multivariate analyses using the Cox proportional hazards model were performed to determine the predictive factors for early BCR (within 1-year). RESULTS: A total of 621 patients with negative surgical margins who did not receive adjuvant therapy were included in this study. The index tumor were located in the transitional zone in 191 patients (30.8%), the peripheral zone in 399 patients (64.3%), and the central zone in 31 patients (5.0%). In total, 22 of 621 patients (3.5%) experienced early BCR and 70 patients (11.2%) experienced overall BCR at a median follow-up of 61.7 months. According to the index tumor location, the early BCR-free rates were 99.5%, 95.7 %, and 83.3% in the transitional, peripheral, and central zones, respectively. On multivariate analysis, the index tumor in the central zone was an independent predictor of early BCR with negative surgical margins following radical prostatectomy, followed by prostatectomy pathological grade, index tumor in the peripheral zone, and high prostate-specific antigen level. CONCLUSIONS: We assessed the significance of index tumor location in patients with negative surgical margins following radical prostatectomy. Index tumors located in the central zone, although infrequent, were the strongest predictive factors for early BCR. Our results may allow urologists and patients to reconsider the therapeutic strategies for prostate cancer.

Amendments in surgical pathology reports: An 8-year institutional experience.

Surgical pathology reports may undergo revisions broadly categorized as addenda (supplementary information) or amendments (changes to finalized reports). Amendments indicate potential flaws in the diagnostic process and serve as important indicators of vulnerabilities in the histopathology workflow. This study analyzed the frequency and distribution of amendments in surgical pathology reports over 8 years to identify patterns highlighting opportunities for improvement. Surgical biopsies, excisions, and resections were included; cytology and molecular tests were excluded. Amended reports were categorized using previously used taxonomy documented in literature. Defects were classified as misinterpretations, misidentifications, defective specimens, or defective reports. Of 101,355 reports, 155 (0.15 %) were signed out with amendments. The amendment rate was approximately 1-2 cases per 1000 reports annually. Misinterpretations accounted for the majority (52 %) of amended reports, with undercalls (62 %) and overcalls (27 %) being predominant subtypes. Tumor staging was amended in 57 (37 %) cases, with 30 being upstaged and 11 downstaged clinically. The highest number of misinterpretation defects occurred in head and neck (36 %) and breast (21 %) specimens. Misinterpretation defects were present in 53 % of malignant cases versus 42 % of benign cases. In 18 cases, there were significant changes in pathological diagnosis (14 major and 4 minor). A standard taxonomy categorizing report defects is crucial for measuring and improving quality control. Accurate pathology reporting impacts patient care and guides workflow improvements. This taxonomy enables us to track variations and deficiencies in our pathology reporting processes in a reproducible way across the department.

[In the face of climate change, is a relevant and sustainable eco-pathology in France possible?] / Face au changement climatique, un écosoin pertinent et sobre en anatomo-pathologie en France est-il possible ?

INTRODUCTION: The healthcare sector is a major contributor to greenhouse gas emissions, accounting for 8 % of annual French emissions. Eco-design in healthcare, which provides care with equal quality, safety, and relevance but with a lower environmental impact, is therefore a crucial lever for sustainable medical practice. This article explores the application of eco-design in anatomical and cytopathological practices (ACP) in France, in response to the country's decarbonization goals. OBJECTIVES: After demonstrating that decarbonization is possible through the chosen eco-design of care and practices in ACP, we describe the barriers to these changes and the potential real-world solutions. DISCUSSION: We examine the challenges and solutions for integrating eco-design principles into daily ACP practice, highlighting the importance of the relevance of medical procedures to reduce unnecessary practices. We discuss the technical and human barriers in ACP, as well as the solutions: raising awareness among laboratory personnel, industrial stakeholders, research and innovation, the involvement of scientific societies, and initiatives from the collective for Ecological Transformation in ACP (TEAP). Finally, we propose financial incentives to make eco-friendly practices economically viable in ACP. CONCLUSION: Eco-design in ACP practices is essential to address the climate challenge and ensure the sustainability of the healthcare system.

[The errors in intravital pathologicoanatomic diagnostic: a publications review].

The review presents analysis of scientific publications considering medical errors in intravital pathologicoanatomic diagnostic. The examples of classification, rate of diagnostic errors and possible ways of decreasing the number of diagnostic errors in pathological anatomy are considered.

Noninferiority of Artificial Intelligence-Assisted Analysis of Ki-67 and Estrogen/Progesterone Receptor in Breast Cancer Routine Diagnostics.

Image analysis assistance with artificial intelligence (AI) has become one of the great promises over recent years in pathology, with many scientific studies being published each year. Nonetheless, and perhaps surprisingly, only few image AI systems are already in routine clinical use. A major reason for this is the missing validation of the robustness of many AI systems: beyond a narrow context, the large variability in digital images due to differences in preanalytical laboratory procedures, staining procedures, and scanners can be challenging for the subsequent image analysis. Resulting faulty AI analysis may bias the pathologist and contribute to incorrect diagnoses and, therefore, may lead to inappropriate therapy or prognosis. In this study, a pretrained AI assistance tool for the quantification of Ki-67, estrogen receptor (ER), and progesterone receptor (PR) in breast cancer was evaluated within a realistic study set representative of clinical routine on a total of 204 slides (72 Ki-67, 66 ER, and 66 PR slides). This represents the cohort with the largest image variance for AI tool evaluation to date, including 3 staining systems, 5 whole-slide scanners, and 1 microscope camera. These routine cases were collected without manual preselection and analyzed by 10 participant pathologists from 8 sites. Agreement rates for individual pathologists were found to be 87.6% for Ki-67 and 89.4% for ER/PR, respectively, between scoring with and without the assistance of the AI tool regarding clinical categories. Individual AI analysis results were confirmed by the majority of pathologists in 95.8% of Ki-67 cases and 93.2% of ER/PR cases. The statistical analysis provides evidence for high interobserver variance between pathologists (Krippendorff's α, 0.69) in conventional immunohistochemical quantification. Pathologist agreement increased slightly when using AI support (Krippendorff α, 0.72). Agreement rates of pathologist scores with and without AI assistance provide evidence for the reliability of immunohistochemical scoring with the support of the investigated AI tool under a large number of environmental variables that influence the quality of the diagnosed tissue images.

Cancer Registration, Molecular Marker Status, and Adherence to the WHO 2016 Classification of Pathology Reports for Glioma Diagnosed during 2017-2019 in Belgium.

INTRODUCTION: The objective of this study was to cross-check and, if necessary, adjust registered ICD-O-3 topography and morphology codes with the findings in pathology reports available at the Belgian Cancer Registry (BCR) for glioma patients. Additionally, integration of molecular markers in the pathological diagnosis and concordance with WHO 2016 classification is investigated. METHODS: Since information regarding molecular tests and corresponding conclusions are not available as structured data at population level, a manual screening of all pseudonymized pathology reports available at the BCR for registered glioma patients (2017-2019) was conducted. ICD-O-3 morphology and topography codes from the BCR database (based on information as provided by hospital oncological care programmes and pathology laboratories), were, at tumour level, cross-checked with the data from the pathology reports and, if needed, specified or corrected. Relevant molecular markers (IDH1/2, 1p19q codeletion, promoter region of the MGMT gene [MGMTp]) were manually extracted from the pathology reports. RESULTS: In 95.3% of gliomas, the ICD-O-3 morphology code was correct. Non-specific topography codes were specified in 9.3%, while 3.3% of specific codes were corrected. The IDH status was known in 75.2% of astrocytic tumours. The rate of correct integrated diagnoses varied from 47.6% to 56.4% among different gliomas. MGMTp methylation status was available in 32.2% of glioblastomas. CONCLUSION: Both the integration of molecular markers in the conclusion of the pathology reports and the delivery of those reports to the BCR can be improved. The availability of distinct ICD-O-3 codes for each molecularly defined tumour entity within the WHO classification would increase the consistency of cancer registration, facilitate population level research and international benchmarking.

Increasing access to pathology services in low- and middle-income countries through innovative use of telepathology.

INTRODUCTION: In low- and middle-income countries (LMICs), surgical care can be limited by access to pathology services. In Uganda, the pathologist-to-population ratio is less than 1 to 1 million people. The Kyabirwa Surgical Center in Jinja, Uganda, created a telepathology service in collaboration with an academic institution in New York City. This study demonstrated the feasibility and considerations of implementing a telepathology model to supplement the critical pathology needs of a low-income country. METHODS: This was a retrospective, single-center study of an ambulatory surgery center with pathology capability using virtual microscopy. The remote pathologist (also known as a telepathologist) controlled the microscope and reviewed histology images transmitted across the network in real time. In addition, this study collected demographics, clinical histories, the surgeon's preliminary diagnoses, and the pathology reports from the center's electronic medical record. RESULTS: Nikon's NIS Element Software was used as a dynamic, robotic microscopy model with a video conferencing platform for communication. An underground fiber optic cable established Internet connectivity. After a two-hour tutorial session, the lab technician and pathologist were able to proficiently use the software. The remote pathologist read (1) pathology slides with inconclusive reports from external pathology labs, and (2) tissues labeled by the surgeon as suspicious for malignancy, which belonged to patients who lacked financial means for pathology services. Between April 2021 and July 2022, tissue samples of 110 patients were examined by a telepathologist. The most common malignancies on histology were squamous cell carcinoma of the esophagus, ductal carcinoma of the breast, and colorectal adenocarcinoma. CONCLUSION: With the increasing availability of video conference platforms and network connections, telepathology is an emerging field that can be used by surgeons in LMICs to improve access to pathology services, confirming histological diagnosis of malignancies to ensure appropriate treatment.

Current Utilization of Electron Microscopy in the Pediatric Pathology Setting: A Survey by the SPP Practice Committee.

BACKGROUND: Electron microscopy (EM), once an important component in diagnosing pediatric diseases, has experienced a decline in its use. To assess the impact of this, pediatric pathology practices were surveyed regarding EM services. METHODS: The Society of Pediatric Pathology Practice Committee surveyed 113 society members from 74 hospitals. Settings included 36 academic tertiary, 32 free-standing children's, and 6 community hospitals. RESULTS: Over 60% maintained in-house EM services and had more than 2 pathologists interpreting EM while reporting a shortage of EM technologists. Freestanding children's hospitals had the most specimens (100-200 per year) and more diverse specimen types. Hospitals with fewer than 50 yearly specimens often used reference laboratories. Seventeen had terminated all in-house EM services. Challenges included decreasing caseloads due to alternative diagnostic methods, high operating costs, and shortages of EM technologists and EM-proficient pathologists. Kidney, liver, cilia, heart, and muscle biopsies most often required EM. Lung/bronchoalveolar lavage, tumor, skin, gastrointestinal, nerve, platelet, and autopsy samples less commonly needed EM. CONCLUSIONS: The survey revealed challenges in maintaining EM services but demonstrated its sustained value in pediatric pathology. Pediatric pathologists may need to address the centralization of services and training to preserve EM diagnostic proficiency among pathologists who perform ultrastructural interpretations.

Sharp Versus Electric Suction Curettage in Gynecologic Patients Undergoing Evaluation for Abnormal Uterine Bleeding.

STUDY OBJECTIVE: Suction curettage is preferred over sharp curettage in obstetric settings. We compare the quality of operative tissue sampling between sharp curettage and suction curettage using electric vacuum aspiration for nonobstetric abnormal uterine bleeding in reproductive-aged women. DESIGN: A retrospective cohort study. SETTING: Community hospital in Long Island, New York. PATIENTS: Women ages 21 to 45 years (n = 257) who underwent operative curettage procedure for nonobstetric abnormal uterine bleeding. INTERVENTIONS: Independent ratings of specimens from suction curettage using electric vacuum aspiration and sharp curettage by 2 pathologists blinded to method of tissue collection. MEASUREMENTS AND MAIN RESULTS: The primary outcome was percentage of organized tissue, indicative of a higher-quality pathology specimen. Specimens obtained by electric suction curettage (p <.001) had a significantly higher percentage of organized tissue (M = 66.28, SD = 20.33) than sharp curettage (M = 55.51, SD = 24.17). There were no differences between the curettage groups for operative time, blood loss, intraoperative complications, or pathology diagnosis. CONCLUSION: Specimens obtained with suction curettage contained more organized tissue with similar pathologist satisfaction and confidence scores than sharp curettage. We suggest clinicians consider electric suction curettage in the diagnostic workup of abnormal uterine bleeding in reproductive-aged women. In addition, patient-centered benefits include no increase in operative time, blood loss, or complication rate compared with sharp curettage.

Contemporary outcomes of esophageal and gastroesophageal junction neuroendocrine tumors.

Adenocarcinoma and squamous cell esophageal cancers have been extensively studied in the literature. Esophageal neuroendocrine (NET)/carcinoid tumors are less commonly studied and have only been described in small series. The purpose of this study was to describe the demographics and natural history of esophageal NETs, as well as optimal treatments. We hypothesized that surgical resection would be the best treatment of esophageal NETs. The National Cancer Database was used to identify adult patients with esophageal or gastroesophageal junction (GEJ) cancer from 2004 to 2018. Patients were characterized as carcinoid/NET, adenocarcinoma, or squamous cell cancer. Clinical and demographic characteristics were compared between the histology groups. The primary outcome was overall survival, which was assessed by multivariable Cox analysis. Multivariable Cox analysis was also used to analyze factors associated with survival among NET patients who underwent surgery. Among 206,321 patients with esophageal cancer, 1,563 were NETs (<0.01%). Relative to the other two histologies, NETs were associated with younger age, female sex, and advanced clinical stage at diagnosis. Multivariate analysis suggested that NETs were less likely to be treated with surgical resection (OR 0.51, P < 0.001). Nonetheless, surgical resection was associated with improved survival (HR 0.64, P = 0.003). Among patients with NETs who received surgery, neoadjuvant therapy was associated with improved overall survival (HR 0.38, P = 0.013). NET of the esophagus presents with more advanced disease than other common histologies. Among patients with nonmetastatic cancer, surgical resection appears to be the best treatment. Neoadjuvant systemic therapy may offer survival benefit, but future studies are necessary.

Survival outcomes and the prognostic significance of clinicopathological features in patients with endometrial clear cell carcinoma: a 35-year single-center retrospective study.

BACKGROUND: To evaluate the oncological outcomes and the impact of clinicopathological factors on endometrial clear cell carcinoma (ECCC) outcomes. METHODS: Medical records of patients with primary ECCC treated at our center between 1985 and December 2020 were reviewed. Overall survival (OS) and progression-free survival (PFS) were the endpoints. The Kaplan-Meier method and Cox regression analysis were used. RESULTS: In total, 156 patients were included, of whom 59% and 41% had early- and advanced-stage ECCC, respectively. The median age of onset was 61 years, and 80.8% of the patients were postmenopausal. Ninety-two (59%) and 64 (41%) patients had pure ECCC and mixed endometrial carcinoma with clear cell carcinoma (CCC) components, respectively. Mixed pathological components, elevated cancer antigen 125 levels, positive lymphovascular space invasion, deep myometrial invasion, and malignant peritoneal washing cytology (PWC) were more frequently observed in the advanced stage. Thirty-nine patients (25%) experienced relapse and 32 patients (20.5%) died. The 5-year PFS and OS rates for the entire cohort were 72.6% and 79%, respectively. Multivariate analysis showed that advanced-stage disease and positive PWC significantly decreased PFS, while advanced-stage disease and older age (> 61 years) significantly decreased OS. CONCLUSIONS: ECCC is a rare and aggressive type II endometrial carcinoma that is common in older women and patients with advanced-stage disease. Positive PWC was associated with decreased PFS, although its presence did not influence the stage. Positive PWC, and advanced stage and older age were independent negative prognostic factors.

An adrenal cortical adenoma with neuroendocrine-type granules mimicking pheochromocytoma.

Clinical and biochemical presentation of adrenal tumors may rarely conflict with their histologic features. In the present report, we describe a rare case of adrenal neoplasm clinically and biochemically labeled as pheochromocytoma which at histologic examination resulted adrenal cortical tumor. The neoplasm was examined with the electron microscope which revealed the presence of electron-dense neuroendocrine-type granules next to intracytoplasmic lipid droplets. The patient underwent laparoscopic left adrenalectomy which leads to normalization of 24 h urinary metanephrine and normetanephrine. This exceptional entity should be taken into consideration when the clinical and laboratory features conflict with the histological examination. The pathologist can clarify the mixed nature of the tumor by means of the identification of neuroendocrine granules at the electron microscope examination.

Comparison of the number and content of pathology laboratory samples before and after the COVID-19 pandemic.

Coronavirus disease 2019 (COVID-19) has caused respiratory system diseases and affected people's access to healthcare services for diseases other than COVID-19. After the COVID-19 pandemic, changes occurred in the number and content of pathology laboratory samples, related to measures such as reducing the number of outpatient clinics in hospitals, postponing elective surgery, and restricting cancer screening. All samples sent to the pathology laboratory between 2019 and 2020 were included in our study. Biopsy, cytology, histochemical, and immunohistochemical staining and biopsies for malignant cases were evaluated. Changes in sample number and content caused by the pandemic were examined. The number of biopsies was 24 312 in 2019 and 13 208 in 2020. On comparison, a decrease was observed in all parameters. The largest (78.5%) and smallest (11.02%) decreases were observed in examinations of the incoming preparations for consultation (214-46) and Trucut needle biopsies (726-646), respectively. Cases such as appendectomies that require urgent intervention and malignancies that require further examination and diagnosis are the least affected. However, whether the decrease in cancer screening will affect the early diagnosis and treatment of malignancies and create a public health problem in the future remains to be established.

Piloleiomyosarcoma in cats: Histological and immunohistochemical features.

This study describes the histomorphology and immunohistochemical profile of 9 cases of feline piloleiomyosarcoma. Cats ranged in age from 7 to 16 years (mean 10), and tumors were 7 to 24 mm in diameter (mean 15). Tumors were composed of fusiform cells that were haphazardly arranged or in variably sized interwoven bundles. Neoplastic cells had eosinophilic and fibrillar cytoplasm, and elongated blunt-ended nuclei. Entrapment of hair follicles and absence of vascular components support an origin from the smooth muscle cells of the arrector pili. Additional findings included bizarre nuclei and giant cells (7/9 cases), atypical mitoses (7/9 cases), ulceration (3/9 cases), and intratumoral necrosis (6/9 cases). Neoplastic cells expressed calponin, desmin, α-smooth muscle actin, and vimentin, but not CD18, CD31, cytokeratins, glial fibrillary acidic protein, neuron-specific enolase, Melan A, p63, or S-100 protein. Surgical excision was curative in 6/9 cases, with local recurrence in 2/9 cases and metastasis to local lymph nodes in 1/9 case. Clinical outcome was influenced by mitotic count, infiltration of subcutaneous tissue, and intensity of nuclear immunolabeling for p53.

Epitheliosis is a histopathological finding associated with malignancy and poor prognosis in dogs with mammary tumors.

Canine mammary epitheliosis (ME) is a poorly studied dysplasia that may have premalignant potential. In this study, the clinicopathological relevance of ME was prospectively studied in 90 female dogs with mammary tumors (MTs) that underwent radical mastectomy. ME distribution, extent, and coexistence with benign and malignant MTs were evaluated for each case (505 mammary glands). ME was macroscopically undetectable and was present in 47/90 (52%) cases, frequently bilateral. In dogs with malignant MTs and ME, diffuse ME throughout the mammary chain was present in 10/39 (26%) cases. A histological ME-carcinoma transition was evident in certain histotypes. By immunohistochemistry (AE1/AE3, cytokeratin 14 [CK-14], CK-8/18, vimentin, calponin, p63, Ki-67, estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2), ME was a slow-growing, triple-negative process with a strong predominance of basal-like nonmyoepithelial cells. ME was associated with older dogs (P = .016), malignant tumors (P = .044), worse clinical stages (P = .013), lymph node metastasis (LNM, P = .021), higher histological grade tumors (P = .035), and shorter overall survival (OS) in univariate analysis (P = .012). Interestingly, ME was distantly located to the malignant tumor in most cases (P = .007). In multivariate analyses, LNM (P = .005), histological grade (P = .006), and tumor size (P = .006) were independent predictors of OS. For the pathologist, the observation of ME should be clearly stated in the MT biopsy report to alert the surgeon/oncologist. Given the differences between canine ME and its human histopathological counterpart (atypical ductal hyperplasia), "epitheliosis" should remain the preferred term for the dog.