Faculty Bibliography

Spread through air spaces (STAS) is reportedly associated with worse prognosis in sublobar resections of lung adenocarcinoma. Recently, it was proposed that STAS detected on frozen sections can be an indication for lobectomy instead of sublobar resection. We undertook this study to evaluate the reliability of STAS assessment on frozen sections compared to permanent sections, as well as the associations among STAS, tumor grade, and recurrence-free survival (RFS) after sublobar resection. A total of 163 stage I lung adenocarcinoma resections with frozen sections were identified retrospectively. For each case, and for frozen and permanent sections separately, the presence or absence of STAS, as well as the tumor grade, were recorded. Compared to permanent sections, STAS detection on frozen sections had low sensitivity (55%), low positive predictive value (48%), and fair agreement (K = 0.34), whereas there was higher specificity (80%) and negative predictive value (85%). Accuracy was 74%. Tumor grade assessment on frozen sections showed higher sensitivity (77%), positive predictive value (90%), agreement (K = 0.72), specificity (94%), and accuracy (87%), and the same negative predictive value (85%). High-grade histology on frozen sections was associated with shorter RFS (p = 0.02), whereas STAS on frozen sections was not (p = 0.47). Our results suggest that the intraoperative detection of STAS has low sensitivity and positive predictive value. False-positive results may lead to overtreatment of patients with lung cancer. The determination of tumor grade on frozen sections offers better sensitivity and specificity, plus it is associated with RFS, whereas STAS on frozen sections is not. Further study is needed to explore the utility of assessing tumor grade on frozen sections.

BACKGROUND:Histological analyses of deep vein thrombi (DVT) are based on autopsy samples and animal models. No prior study has reported on thrombus composition following percutaneous mechanical extraction. As elements of chronicity and organization render thrombus resistant to anticoagulation and thrombolysis, a better understanding of clot evolution may inform therapies. METHODS:We performed histologic evaluation of DVTs from consecutive patients undergoing mechanical thrombectomy for extensive iliofemoral DVTs using the Clottriever/ Flowtriever device (Inari Medical, Irvine, CA). Thrombi were scored in a semi-quantitative manner based on the degree of fibrosis (collagen deposition on trichrome stain), and organization (endothelial growth with capillaries and fibroblastic penetration). RESULTS:Twenty-three specimens were available for analysis with 20 presenting with acute DVT (≤14 days from symptom onset). Eleven of 23 patients (48%) had >5% fibrosis (collagen deposition) and 14/23 patients (61%) had >5% organization (endothelial growth, capillaries, fibroblasts). Four patients with acute DVT had ≥25% organized thrombus and 2 had ≥ 25% collagen deposition. Among the 20 patients with acute DVT, 40% had >5% fibrosis and 55% had > 5% organization. Acuity of DVT did not correlate with the fibrosis or organizing scores. CONCLUSIONS:A large proportion of patients with acute DVT have histologic elements of chronicity and fibrosis. A better understanding of the relationship between such elements and response to anticoagulants and fibrinolytics may inform our approach to therapeutics.

There is growing evidence that molecular testing is feasible on all types of cytological preparation, which is fortunate as more diagnostic markers and biomarkers for targeted therapies are discovered for use in pulmonary and pleural malignancies. In this article we will discuss the pre-analytic, analytic, and post-analytic (interpretive) considerations for successful implementation of molecular tests for diagnostic and predictive markers in respiratory and pleural cytology. The vast majority of laboratories are familiar with, and have validated their molecular protocols for, formalin-fixed paraffin-embedded surgical specimens, which are not directly applicable to cytology specimens. Thus, rigorous validation must be performed for each type of fixative and cytology preparation before it is implemented in the clinical setting.

Infective endocarditis (IE) is a life-threatening disease associated with in-hospital mortality of nearly one in five cases. IE can destroy valvular tissue, which may rarely progress to aneurysm formation, most commonly at the anterior leaflet in instances of mitral valve involvement. We present a remarkable case of a patient with IE and a rare complication of a ruptured aneurysm of the posterior leaflet of the mitral valve. Two- and Three-dimensional transesophageal echocardiography, intra-operative videography, and histopathologic analysis revealed disruption at this unusual location-at the junction of the P2 and P3 scallops, surrounded by an annular abscess.

Screening for therapeutic targets is standard of care in the management of advanced non-small cell lung cancer. However, most molecular assays utilize tumor tissue, which may not always be available. "Liquid biopsies" are plasma-based next generation sequencing (NGS) assays that use circulating tumor DNA to identify relevant targets. To compare the sensitivity, specificity, and accuracy of a plasma-based NGS assay to solid-tumor-based NGS we retrospectively analyzed sequencing results of 100 sequential patients with lung adenocarcinoma at our institution who had received concurrent testing with both a solid-tissue-based NGS assay and a commercially available plasma-based NGS assay. Patients represented both new diagnoses (79%) and disease progression on treatment (21%); the majority (83%) had stage IV disease. Tissue-NGS identified 74 clinically relevant mutations, including 52 therapeutic targets, a sensitivity of 94.8%, while plasma-NGS identified 41 clinically relevant mutations, a sensitivity of 52.6% (p < 0.001). Tissue-NGS showed significantly higher sensitivity and accuracy across multiple patient subgroups, both in newly diagnosed and treated patients, as well as in metastatic and nonmetastatic disease. Discrepant cases involved hotspot mutations and actionable fusions including those in EGFR, ALK, and NTRK1. In summary, tissue-NGS detects significantly more clinically relevant alterations and therapeutic targets compared to plasma-NGS, suggesting that tissue-NGS should be the preferred method for molecular testing of lung adenocarcinoma when tissue is available. Plasma-NGS can still play an important role when tissue testing is not possible. However, given its low sensitivity, a negative result should be confirmed with a tissue-based assay.