Personalized Medicine in Histiocytic Disorders: Novel Targets in Patients Without MAPK Alterations.

Purpose: BRAF and MEK inhibitors are standard treatments in histiocytic disorders, such as Erdheim-Chester disease (ECD). Some patients lack MAPK-pathway alterations, making these treatments less effective.

Methods: We describe three patients with histiocytic disorders who have novel non-MAPK pathway alterations.

Asymptomatic Takayasu Arteritis With Critical Multivessel Stenosis.

Takayasu arteritis is characterized by blood vessel inflammation involving the aorta and its branches. We describe a patient with Takayasu arteritis with severe multivessel involvement and classic physical examination findings but virtually no symptoms because of the presence of extensive collateral circulation seen on computed tomography angiography and magnetic resonance angiography imaging.

Clinical characteristics, molecular aberrations, treatments, and outcomes of malignant histiocytosis.

Malignant histiocytosis (MH) is an extremely rare neoplasm of the macrophage-dendritic cell lineage. We report the clinical characteristics, molecular aberrations, treatments, and outcomes of patients with MH seen at two referral centers from January 2000 to May 2023. We identified 43 patients with MH, of which 26 had histiocytic sarcoma (MH-H), 9 interdigitating dendritic cell sarcoma (MH-IDC), and 8 Langerhans cell sarcoma (MH-LC).

Long-term outcomes among adults with Langerhans cell histiocytosis.

Advances in the treatment of Langerhans cell histiocytosis (LCH) have resulted in a growing survivor population. There is a lack of data on long-term outcomes among adults with LCH. We conducted a retrospective record review of 219 adults (aged ≥18 years) with LCH.

FDG PET/CT and thyroid biopsy leads to neurosarcoidosis diagnosis.

We present a unique case of neurosarcoidosis diagnosed based on thyroid biopsy and FDG PET (Fluorodeoxyglucose positron emission tomography) imaging. A patient presented for a second opinion after being placed in hospice for rapidly progressing dementia, presumed to be due to Creutzfeldt Jakob disease despite negative workup and was unable to perform activities of daily life or communicate with his wife. The patient underwent a workup including whole-body FDG PET, which showed hypermetabolic lymph nodes as well as a hypermetabolic nodule in the thyroid.

Malignant Histiocytosis Comprises a Phenotypic Spectrum That Parallels the Lineage Differentiation of Monocytes, Macrophages, Dendritic Cells, and Langerhans Cells.

Malignant histiocytoses (MHs), or the 'M group' of the Histiocyte Society classification, are characterized by neoplastic histiocytes with large pleomorphic nuclei. MH encompasses the diagnoses of histiocytic sarcoma, interdigitating dendritic cell sarcoma, and Langerhans cell sarcoma. We aimed to define the phenotypic spectrum of MH and examine the genotypic features across this spectrum.

Neurological Manifestations of Histiocytic Disorders.

Purpose Of Review: Histiocytic disorders, including Erdheim-Chester disease (ECD), Langerhans cell histiocytosis (LCH), and Rosai-Dorfman disease (RDD), are rare neoplasms that may present with a spectrum of neurologic involvement. Diagnostic delay is common due to heterogeneity in presentation and challenging pathology.

Recent Findings: Recent advances in the treatment of these diseases targeted towards mutations in the MAP kinase pathway have led to an improved prognosis in these patients with neurologic involvement.

Bayesian penalized likelihood PET reconstruction impact on quantitative metrics in diffuse large B-cell lymphoma.

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.

Safety and Efficacy of CT-Guided Percutaneous Biopsy of Suspicious Subcentimeter Pelvic and Retroperitoneal Lymph Nodes Detected by C-Choline PET in Patients With Prostate Cancer.

In patients with prostate cancer, PET using targeted radiotracers can identify increased activity in small morphologically normal lymph nodes, facilitating earlier detection of metastatic disease. The purpose of this article was to assess the efficacy and safety of CT-guided biopsy of suspicious pelvic and retroperitoneal lymph nodes measuring smaller than 1 cm detected by C-choline PET in patients with prostate cancer, with comparison with nodes measuring 1 cm or larger. This retrospective study included patients with prostate cancer who underwent CT-guided percutaneous biopsy of suspicious pelvic or retroperitoneal lymph nodes detected by C-choline PET/CT or PET/MRI (performed because of a rising or elevated PSA level or known recurrent or metastatic disease) between June 1, 2012, and March 20, 2020.

Technologist-Based Implementation of Total Metabolic Tumor Volume into Clinical Practice.

Metabolic tumor volume (MTV) is defined as the total metabolically active tumor volume seen on F-FDG PET/CT examinations. Calculating MTV is often time-consuming, requiring a high degree of manual input. In this study, the MTV calculations of a board-certified nuclear radiologist were compared with those of 2 nuclear medicine technologists.

Ophthalmologic Involvement in Adults with Histiocytic Disorders: Clinical Presentation and Treatment Outcomes.

Purpose: To evaluate the clinical presentation, treatment, and outcomes in adult patients with histiocytic disorders with ocular, orbital, optic nerve, or cavernous sinus involvement.

Design: Observational, retrospective chart review.

Participants: Adult patients (age ≥ 18 years) at Mayo Clinic from January 1, 1996, to July 1, 2021, with histiocytic disorders.

Impact of a Multidisciplinary Tumor Board on the Care of Patients with Histiocytic Disorders: The Histiocytosis Working Group experience.

Introduction: Histiocytic disorders pose significant diagnostic and management challenges for the clinicians due to diverse clinical manifestations and often non-specific histopathologic findings. Herein, we report the tumor board experience from the first-of-its-kind Histiocytosis Working Group (HWG).

Materials And Methods: The HWG was established in June 2017 and consists of experts from 10 subspecialties that discuss cases in a multidisciplinary format.