Rosai Dorfman Disease

The purpose of the study is to describe the burden of chronic health conditions, psychological dysfunction, chronic pain, healthcare utilization, worse health-related quality of life, overall mortality, and cause-specific mortality among individuals with histiocytic disorders

The purpose of this study is to determine the uptake of the imaging agent \[68Ga\]-pentixafor with PET/CT scans in people with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and non-Hodgkin lymphoma (NHL), or you have histiocytic neoplasms (Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD) and/or Rosai-Dorfman disease (RDD).

In patients with Rosai-Dorfman disease (RDD), a treatment regimen of lenalidomide combined with dexamethasone is planned to be used.

This is a research study of a drug called cobimetinib in children and adults diagnosed with Langerhans cell histiocytosis (LCH), and other histiocytic disorders that has returned or does not respond to treatment. Cobimetinib blocks activation of a protein called Mitogen-activated protein kinase (MEK) that is part of incorrect growth signals in histiocytosis cells. Four different groups of patients will be enrolled.