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).

Inclusion Criteria:

Twenty patients with histologically proven treatment-naïve, therapy-refractory or relapsed blood cancers meeting the below criteria will be included:

• Indolent B- or T-cell Non-Hodgkin lymphoma (including cutaneous lymphomas) or Non-Hodgkin lymphoma with variable FDG uptake and clinical course, such as mantle cell lymphoma; and measurable disease according to Lugano criteria

or

• Histiocytic neoplasms (Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD) and/or Rosai-Dorfman disease (RDD)
• MGUS/SMM or MM according to IMWG definitions
• Solid tumors, such as lung cancers, meningioma, adrenocortical neoplasms including cortisol-producing adenomas or high suspicion for tumor, such as in patients with Cushing's disease.
• Age ≥18
• Negative serum pregnancy test for female volunteers of childbearing age and potential (as defined by MSKCC Standards & Guidelines) from assays obtained <2 weeks prior to study enrollment/intervention; or negative urine pregnancy test performed on the day of intervention
• MSKCC patients

Exclusion Criteria:

• Breast-feeding
• History of renal functional disorders (chronic kidney disease with eGFR<30)
• Refusal or inability to tolerate the scanning procedure (e.g., due to claustrophobia)

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.