Erroneous Patient Tissue Contaminants in 1574 Surgical Pathology Slides: Impact on Diagnostic Error and a Novel Framework for Floater Management.

CONTEXT.­: Tissue contaminants on histology slides represent a serious risk of diagnostic error. Despite their pervasive presence, published peer-reviewed criteria defining contaminants are lacking. The absence of a standardized diagnostic workup algorithm for contaminants contributes to variation in management, including investigation and reporting by pathologists. OBJECTIVE.­: To study the frequency and type of tissue contaminants on microscopic slides using standardized criteria. Using these data, we propose a taxonomy and algorithm for pathologists on "floater" management, including identification, workup, and reporting, with an eye on patient safety. DESIGN.­: A retrospective study arm of 1574 histologic glass slides as well as a prospective study arm of 50 slide contamination events was performed. Using these data we propose a structured classification taxonomy and guidelines for the workup and resolution of tissue contamination events. RESULTS.­: In the retrospective arm of the study, we identified reasonably sized benign tissue contaminants on 52 of 1574 slides (3.3%). We found size to be an important parameter for evaluation, among other visual features including location on the slide, folding, ink, and tissue of origin. The prospective arm of the study suggested that overall, pathologists tend to use similar features when determining management of potentially actionable contaminants. We also report successfully used case-based ancillary testing strategies, including fluorescence in situ hybridization analysis of chromosomes and DNA fingerprinting. CONCLUSIONS.­: Tissue contamination events are underreported and represent a patient safety risk. Use of a reproducible classification taxonomy and a standardized algorithm for contaminant workup, management, and reporting may aid pathologists in understanding and reducing risk.

Thyroid Mucosa-associated Lymphoid Tissue Lymphoma Presenting as Intermediate-risk Thyroid Nodule with Positive KRAS Mutation.

Background: /Objective: Little is known about the epidemiology, clinical presentation, and diagnosis of thyroid mucosa-associated lymphoid tissue (MALT) lymphoma. Case Report: We report the case of a 67-year-old woman who presented with an intermediate-risk thyroid nodule 8 years after diagnosis of hypothyroidism due to Hashimoto's. She was found to have a well-circumscribed hypoechoic 2.6-cm right-sided thyroid nodule lobe, which was biopsied and returned atypia of undetermined significance with positive KRAS mutation on the Thyroseq V3 Genomic Classifier. She subsequently underwent right thyroid lobectomy and was found to have thyroid MALT lymphoma on histopathological sections. After the surgery, she was referred to oncology for further management of the thyroid MALT lymphoma. A positron emission tomography/computed tomography scan was performed for complete staging and revealed diffuse fluorodeoxyglucose uptake in the residual left thyroid lobe without evidence of extrathyroidal involvement. Her case was discussed in a multidisciplinary fashion among oncology, endocrine surgery, and endocrinology. Given the positron emission tomography scan findings, she ultimately underwent completion thyroidectomy 4 months after the initial surgery to rule out residual disease. The patient tolerated the operation well without complication. Discussion: Our report adds to the literature that Hashimoto's thyroiditis may be a risk factor of thyroid MALT lymphoma. Localized thyroid MALT lymphoma may be managed with total thyroidectomy. Conclusion: We report a patient with localized thyroid MALT lymphoma who presented with an intermediate-risk nodule with positive KRAS mutation and was treated with total thyroidectomy.

Rapid histological imaging of bone without microtome sectioning using nonlinear microscopy.

Tissue preparation for histologic evaluation of bone is particularly lengthy, limiting its use in intraoperative or intraprocedural histological evaluation. Nonlinear microscopy (NLM) is an optical sectioning microscopy method that can visualize pathology in freshly excised tissue without requiring physical microtome sectioning. This study describes a rapid protocol for NLM imaging of bone and associated cartilage. NLM imaging was performed on 71 specimens of normal bone as well as arthritic, malignant and inflammatory bone tissue from 40 patients who underwent joint replacement, amputation, bone marrow biopsy or autopsy. Specimens ranged in size from core needle biopsies to transections of entire femoral heads. Specimens were stained with acridine orange and sulforhodamine 101, nuclear and cytoplasmic/stromal fluorescent dyes, for 5 min, then rinsed for 30 s. NLM fluorescent images were displayed using colors analogous to hematoxylin and eosin (H&E) to facilitate interpretation. Pathologists examined NLM images of the specimens in real time by rapidly translating the specimen to areas of interest, similar to a standard transmission light microscope. By adjusting the NLM focus depth, images from a few-µm-thick layer could be obtained down to ~100 µm below the tissue surface, analogous to serial sectioning. Following real-time NLM imaging, the tissue was processed for conventional paraffin histology, and H&E slides were compared to recorded NLM images. Similarities and differences between NLM and paraffin H&E were assessed. NLM enabled visualization of normal bone architecture, including the lamellar matrix and osteocytes of trabecular bone, articular cartilage, as well as pathological bone features such osteoarthritis, osteomyelitis, and malignancy with an appearance resembling the paraffin H&E. Differences such as changes in cell border sharpness, cellular and nucleolar size, and color patterns were noted, suggesting that training is required for accurate evaluation of bone pathology with NLM. Irregular surface contours and debris generated by gross tissue preparation of bone can make some regions difficult to evaluate with NLM, but the ability to perform rapid three-dimensional translation and sub-surface imaging reduced these problems. NLM is a promising technique for rapid evaluation of bone pathology. Further studies assessing diagnostic performance are warranted.

Not the usual suspect: Polymeric IgA paraprotein causes false positive results in kinetic interaction of microparticles in solution (KIMS) immunoassays.

Immunoassays are commonly used by the clinical laboratory, but paraproteins can occasionally produce erroneous results. In this study, we investigated the cause of apparent false positive results for multiple Kinetic Interaction of Microparticles in Solution (KIMS) immunoassays. Patient controls and samples containing the interference were analyzed using automated chemistry platforms, gel electrophoresis, immunofixation, affinity chromatography, and size exclusion chromatography. Our results show that IgA paraprotein caused false positive results for the KIMS measurement of three therapeutic drugs. To our knowledge, this is the first report of IgA paraprotein-causing immunoassay interference. The clinical implications of this interference are discussed.

Why Have Detection, Understanding and Management of Kidney Hypoxic Injury Lagged Behind those for the Heart?

The outcome of patients with acute myocardial infarction (AMI) has dramatically improved over recent decades, thanks to early detection and prompt interventions to restore coronary blood flow. In contrast, the prognosis of patients with hypoxic acute kidney injury (AKI) remained unchanged over the years. Delayed diagnosis of AKI is a major reason for this discrepancy, reflecting the lack of symptoms and diagnostic tools indicating at real time altered renal microcirculation, oxygenation, functional derangement and tissue injury. New tools addressing these deficiencies, such as biomarkers of tissue damage are yet far less distinctive than myocardial biomarkers and advanced functional renal imaging technologies are non-available in the clinical practice. Moreover, our understanding of pathogenic mechanisms likely suffers from conceptual errors, generated by the extensive use of the wrong animal model, namely warm ischemia and reperfusion. This model parallels mechanistically type I AMI, which properly represents the rare conditions leading to renal infarcts, whereas common scenarios leading to hypoxic AKI parallel physiologically type II AMI, with tissue hypoxic damage generated by altered oxygen supply/demand equilibrium. Better understanding the pathogenesis of hypoxic AKI and its management requires a more extensive use of models of type II-rather than type I hypoxic AKI.

Agonists for the Chemokine Receptor CXCR4.

The development of agonists for the chemokine receptor CXCR4 could provide promising therapeutic candidates. On the basis of previously forwarded two site model of chemokine-receptor interactions, we hypothesized that linking the agonistic N-terminus of SDF-1 to the T140 backbone would yield new high-affinity agonists of CXCR4. We developed chimeras with the agonistic SDF-1 N-terminus grafted to a T140 side chain and tested their binding affinity and chemotactic agonist activity. While chimeras with the peptide grafted onto position 12 of T140 remained high-affinity antagonists, those bearing the peptide on position 14 were in part agonists. One chimera was a full CXCR4 agonist with 25 nM affinity, and several chimeras showed low nanomolar affinities with partial agonist activity. Our results confirmed that we have developed high-affinity agonists of CXCR4.