Comparison of laboratory methods for the detection of neoplastic plasma cells in plasma cell dyscrasias.

AIMS: To compare the ability of immunohistochemistry (IHC), multiparameter flow cytometry (MFC) and fluorescence in situ hybridisation (FISH) to detect clonal plasma cells. We also attempted to outline a testing strategy for monitoring multiple myeloma patients. METHODS: A retrospective review was performed on 278 CD138+sorted FISH studies from November 2019 to December 2020 along with their concurrent IHC and MFC results. A p value was computed using McNemar's test for paired data. Association was calculated using the non-parametric Spearman correlation coefficient. RESULTS: Using the Mc Nemar's test for paired data, CD138+sorted FISH studies achieved the highest proportion of positive results and was significantly greater than MFC (63% vs 53%, p=0.01). FISH had more positive results than IHC, although this did not reach statistical significance (60% vs 57%, p=0.34). IHC and MFC had high correlation and high agreement (90.3% agreement, kappa=0.805, p<0.0001). CD138+sorted FISH studies achieved the highest proportion of positive results relative to IHC and MFC, indicating that it may be a reliable marker for clonal plasma cell detection. CONCLUSIONS: While CD138+sorted FISH is primarily used for prognostication, it may be employed as a single test for detection and monitoring clonality in certain scenarios. Further studies are needed to monitor the outcomes of patients with positive FISH and negative IHC and MFC. Additionally, there was high agreement between IHC and MFC, suggesting that performing both tests may not be necessary.

Systematically higher Ki67 scores on core biopsy samples compared to corresponding resection specimen in breast cancer: a multi-operator and multi-institutional study.

Ki67 has potential clinical importance in breast cancer but has yet to see broad acceptance due to inter-laboratory variability. Here we tested an open source and calibrated automated digital image analysis (DIA) platform to: (i) investigate the comparability of Ki67 measurement across corresponding core biopsy and resection specimen cases, and (ii) assess section to section differences in Ki67 scoring. Two sets of 60 previously stained slides containing 30 core-cut biopsy and 30 corresponding resection specimens from 30 estrogen receptor-positive breast cancer patients were sent to 17 participating labs for automated assessment of average Ki67 expression. The blocks were centrally cut and immunohistochemically (IHC) stained for Ki67 (MIB-1 antibody). The QuPath platform was used to evaluate tumoral Ki67 expression. Calibration of the DIA method was performed as in published studies. A guideline for building an automated Ki67 scoring algorithm was sent to participating labs. Very high correlation and no systematic error (p = 0.08) was found between consecutive Ki67 IHC sections. Ki67 scores were higher for core biopsy slides compared to paired whole sections from resections (p ≤ 0.001; median difference: 5.31%). The systematic discrepancy between core biopsy and corresponding whole sections was likely due to pre-analytical factors (tissue handling, fixation). Therefore, Ki67 IHC should be tested on core biopsy samples to best reflect the biological status of the tumor.

Feasibility of a deep learning algorithm to distinguish large cell neuroendocrine from small cell lung carcinoma in cytology specimens.

INTRODUCTION: Distinguishing small cell lung carcinoma (SCLC) from large cell neuroendocrine carcinoma (LCNEC) in cytology is challenging. Our aim was to design a deep learning algorithm for classifying high-grade neuroendocrine carcinomas in fine needle aspirations. METHODS: Archival cytology cases of high-grade neuroendocrine carcinoma (17 small cell, 13 large cell, 10 mixed/unclassifiable) were retrieved. Each case included smears (Diff-Quik® and Papanicolaou stains) and cell block or concomitant core biopsies (haematoxylin and eosin [H&E] stain). All slides (n = 114) were scanned at 40× magnification, randomised and split into training (11 large, nine small) and test (two large, eight small, 10 mixed) groups. Tumour was annotated using QuPath and exported as JPEG image tiles. Three distinct deep learning convolutional neural networks, one for each preparation/stain, were designed to classify each tile and provide an overall diagnosis for each slide. RESULTS: The H&E-trained algorithm correctly classified 7/8 (87.5%) SCLC cases and 2/2 (100%) LCNEC cases. The Papanicolaou stain algorithm correctly classified 6/7 (85.7%) SCLC. and 1/1 (100%) LCNEC cases. The algorithm trained on Diff-Quik® stained images correctly classified 7/8 (87.5%) SCLC and 1/1 (100%) LCNEC cases. CONCLUSION: Using open source software, it was feasible to design a deep learning algorithm to distinguish between SCLC and LCNEC. The algorithm showed high precision in distinguishing between these two categories on H&E sectioned material and direct smears. Although the dataset was limited, our deep learning models show promising results in the classification of LCNEC and SCLC. Additional work using a larger dataset is necessary to improve the algorithm's performance.

Aggressive FUS-Mutant Motor Neuron Disease Without Profound Spinal Cord Pathology.

A 29-year-old man presented with rapidly progressive severe neck weakness, asymmetrical bilateral upper extremity weakness, bulbar dysfunction, profound muscle wasting, and weight loss. Within 1 year, his speech became unintelligible, he became gastrostomy- and tracheostomy/ventilator-dependent, and wheelchair bound. Electrophysiology suggested motor neuron disease. Whole exome sequencing revealed a heterozygous pathogenic variant in the fused in sarcoma gene (FUS), c.1574C>T,p. R525L, consistent with autosomal dominant amyotrophic lateral sclerosis. Autopsy revealed extensive denervation atrophy of skeletal musculature. Surprisingly, there was only minimal patchy depletion of motor neurons within the cervico-thoracic spinal cord anterior horn cells, and the tracts were largely preserved. TDP-43 inclusions were absent. Abnormal expression of FUS mutation product (cytoplasmic inclusions) was demonstrated by immunohistochemistry within anterior horn motor neurons. The most prominent finding was a disparity between profound neck weakness and relatively low-grade anterior horn cell loss or tract degeneration in the cervico-thoracic cord.

Systematic Review of the Use of Telepathology During Intraoperative Consultation.

OBJECTIVE: To compare studies that used telepathology systems vs conventional microscopy for intraoperative consultation (frozen-section) diagnosis. METHODS: A total of 56 telepathology studies with 13,996 cases in aggregate were identified through database searches. RESULTS: The concordance of telepathology with the reference standard was generally excellent, with a weighted mean of 96.9%. In comparison, we identified seven studies using conventional intraoperative consultation that showed a weighted mean concordance of 98.3%. Evaluation of the risk of bias showed that most of these studies were low risk. CONCLUSIONS: Despite limitations such as variation in reporting and publication bias, this systematic review provides strong support for the safety of using telepathology for intraoperative consultations.

Assessing competency for remote telecytology rapid on-site evaluation using pre-recorded dynamic video streaming.

INTRODUCTION: Telecytology using real-time microscopy has gained popularity for rapid on-site evaluations (ROSE). Although proficiency testing is routinely used in cytopathology, no established means of competency assessment is currently available for telecytology. Our aim was to determine the feasibility of a dynamic (real-time) platform to assess telecytology competency. METHODS: Remote Medical Technology dynamic (real-time) video streaming platform for ROSE is used at our institution, and short video clips of telecytology cases were recorded using Camtasia Studio 8 software during different ROSE sessions. Selected MP4 videos (range 13-88 seconds, mean 33 seconds), along with clinical histories, were used to build a multiple-choice question test with one training case and 20 test cases, utilising Tutor (Philips) software to host the web-based test. The test was voluntary for cytopathologists and cytotechnologists. Answers and feedback from test takers were analysed. RESULTS: Thirteen participants-four cytopathologists and nine cytotechnologists-previously trained to use telecytology, volunteered to take the test. Individual scores ranged from 10 (50%) to 19 (95%) with a median of 16 (80%). Most feedback received involved technical difficulties. CONCLUSIONS: We present, to the best of our knowledge, the first tool to assess telecytology competency for ROSE using pre-recorded dynamic streaming videos. Despite technical challenges related to incorporating videos into a web-based test, the test was feasible and provided users with valuable feedback about their ROSE performance. Future effort will be devoted to establishing a more user-friendly test platform and establishing a benchmark for passing scores.

Review of the use of telepathology for intraoperative consultation.

INTRODUCTION: The use of telepathology in intraoperative consultations has been increasing due to limited time and availability of pathologists, and the demand for increased access to pathology subspecialists in difficult cases. The five main categories of telepathology are (1) static, (2) dynamic, (3) robotic, (4) whole slide imaging (WSI), and (5) hybrid methods. The majority of these methods have been found to offer diagnostic accuracy rates similar to conventional microscopy, at the cost of slightly prolonged time to evaluate slides. AREAS COVERED: Herein we discuss the salient features of each telepathology method and provide examples of their performance reported in the literature. EXPERT COMMENTARY: Telepathology systems from any of the aforementioned categories can be employed to achieve timely and accurate diagnoses as long as they meet clinical needs and are validated for the intended use case. The decision to purchase a particular system depends on the clinical application, specific needs and budget of the laboratory, as well as the personal preference of the telepathologists involved. The adoption of telepathology practice is likely to expand in order to meet the increasing demand for subspecialist consultation and as technology advances to improve diagnostic accuracy and workflow.

EBV-associated hepatic smooth muscle tumor of uncertain biologic behavior after heart transplantation in a pediatric patient: case report.

Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT) is a rare neoplasm recognized in immunocompromised patients. There are less than 30 cases of EBV-SMT reported in pediatric population following solid organ transplantation. Herein, we report a case of an 8-year-old female who was incidentally noted to have multiple lesions in the liver 8 years after heart transplantation. The tumor was composed of a cellular proliferation of spindle-shaped cells with low mitotic activity. The diagnosis of EBV-SMT was confirmed by in situ hybridization for EBV-encoded small RNA (EBER) transcripts. Multiple additional lesions were detected by whole body positron emission tomography-computed tomography (PET-CT) scan 4 months after the initial finding of the hepatic lesions. Immunosuppression was switched to a mechanistic target of rapamycin (mTOR) inhibitor. We conclude that EBV-SMT should be included in the differential diagnoses in post-transplantation patients and further investigations should be performed to evaluate additional lesions.

Treatment of IgG4-related pachymeningitis in a patient with steroid intolerance: The role of early use of rituximab.

IgG4-related pachymeningitis is a serious inflammatory condition that can present with symptoms of mass effect and focal deficits. The first-line therapy is steroids and second-line is chemotherapy (methotrexate, azathioprine, etc.). We describe a patient with IgG4-related pachymeningitis in whom steroid use was contraindicated and methotrexate was ineffective. During the course of treatment, the patient presented to the emergency department with receptive and expressive aphasia, slurred speech, right-sided neglect, and loss of sensation. After a single infusion of rituximab and anticonvulsants, her symptoms resolved. Our unique case suggests that patients with IgG4-related pachymeningitis might benefit from early initiation of rituximab.

Recognizing the distinct cytomorphologic features of solid pseudopapillary neoplasm of the pancreas.

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare low-grade malignant tumor with an indolent clinical course and a favorable prognosis that is most commonly seen in young women of reproductive age. We present a case of SPN in a middle-aged man, diagnosed on a limited cytology specimen. Interestingly, this tumor has unique cytomorphologic findings in fine needle aspiration cytology smears, which help distinguish it from other pancreatic lesions. The presence of fibrovascular cores lined by loosely cohesive monomorphic neoplastic cells is a reliable cytomorphologic feature on aspiration cytology. Recognition of this characteristic finding is crucial for the diagnosis of this entity, especially when it presents in unexpected patient populations or when faced with scant cytology specimens. This report focuses on the distinguishing characteristics of SPN and how they compare and contrast with other pancreatic lesions that are in the differential diagnosis of SPN.