Young, Jason R

Erdheim–Chester disease (ECD) is a rare non-Langerhans cell histiocytosis characterised by multiorgan pathological histiocytic infiltration. Cardiac involvement occurs in 40–75% of patients and increases mortality. A 55-year-old woman with chest pain and dyspnoea was found to have an interatrial septal mass and aortitis suspicious for ECD without other organ involvement. After two inadequate transcatheter interatrial biopsies were obtained using ultrasound guidance alone, diagnostic samples were successfully obtained using intraprocedural frozen section examination. The patient started genotype-targeted treatment with good response. Biopsy confirmation of ECD is required to guide treatment; however, cardiac biopsies are uncommonly performed when other organs are affected. Our unique case of isolated cardiovascular involvement highlights how frozen sectioning with multimodal intraprocedural imaging guidance can improve diagnostic yield of endomyocardial biopsies. It also highlights how diagnosis of rare conditions requires careful multidisciplinary evaluation of affected organs, procedural risk and diagnostic yield. The use of frozen sectioning can improve diagnostic yield of endomyocardial biopsies.

Abstract In this retrospective study, BRAF mutation status did not correlate with disease extent or (event-free) survival in 156 adults with Langerhans cell histiocytosis. BRAFV600E was associated with an increased incidence of second malignancies, often comprising hematological cancers, which may be clonally related.

Evaluate the quantitative, subjective (Deauville score [DS]) and reader agreement differences between standard ordered subset expectation maximization (OSEM) and Bayesian penalized likelihood (BPL) positron emission tomography (PET) reconstruction methods. A retrospective review of 104 F-18 fluorodeoxyglucose PET/computed tomography (CT) exams among 52 patients with diffuse large B-cell lymphoma. An unblinded radiologist moderator reviewed both BPL and OSEM PET/CT exams. Four blinded radiologists then reviewed the annotated cases to provide a visual DS for each annotated lesion. Significant (P < .001) differences in BPL and OSEM PET methods were identified with greater standard uptake value (SUV) maximum and SUV mean for BPL. The DS was altered in 25% of cases when BPL and OSEM were reviewed by the same radiologist. Interobserver DS agreement was higher for OSEM (>1 cm lesion = 0.89 and ≤1 cm lesion = 0.84) compared to BPL (>1 cm lesion = 0.85 and ≤1 cm lesion = 0.81). Among the 4 readers, average intraobserver visual DS agreement between OSEM and BPL was 0.67 for lesions >1cm and 0.4 for lesions ≤1 cm. F-18 Fluorodeoxyglucose PET/CT of diffuse large B-cell lymphoma reconstructed with BPL has higher SUV values, altered DSs and reader agreement when compared to OSEM. This report finds volumetric PET measurements such as metabolic tumor volume to be similar between BPL and OSEM PET reconstructions. Efforts such as adoption of European Association Research Ltd accreditation should be made to harmonize PET data with an aim at balancing the need for harmonization and sensitivity for lesion detection.