E1927. Lymphoma in Pregnancy: Optimal Imaging Modalities and Practices
  1. Kevin Dell'Aquila; New York Institute of Technology College of Osteopathic Medicine
  2. Miltiadis Tembelis; NYU Langone
  3. Jonathan Revels; New York University
  4. Douglas Katz; NYU Langone
  5. Mariam Moshiri; Vanderbilt University Medical Center
Hodgkin lymphoma (HL) is the most common hematologic malignancy diagnosed in pregnant women, and the fourth most common cancer overall in pregnancy. Non-Hodgkin lymphoma (NHL) is the next most common malignancy in pregnancy. Diagnosing and staging of malignancy in pregnancy carries risk of radiation exposure to the fetus. Therefore, the incidence of HL and NHL is important to consider in pregnant mothers with weight loss, night sweats, fever, and chills. Lymphoma in pregnancy is understudied. Progress is being made on an optimal imaging protocol for lymphoma, but no formal updates beyond 2014 Lugano classifications recommending PET/CT have been made to our knowledge. There is evidence in the literature that whole-body MRI (WB-MRI) is at least equivalent to PET/CT for staging accuracy with radiation dose elimination. Recent research demonstrates PET/MRI may be a superior modality for identification, staging and monitoring. The current formal recommendation of PET/CT for lymphoma may require revision, especially for the pregnant patient for whom WB-MRI and PET/MRI may outperform PET/CT with radiation dose reduction.

Educational Goals / Teaching Points
There are currently no known studies of identification, staging and monitoring of lymphoma in pregnant women. Although PET/CT is the current standard for staging of lymphomas, CT in pregnancy is a relative contraindication while 18-FDG PET use is controversial. WB-MRI and PET/MRI have shown promise in the literature to be superior to PET/CT for staging of lymphomas in nonpregnant patients. WB-MRI would be the safest and most feasible modality for pregnant women with lymphoma, and PET/MRI may maintain accuracy while offering prognostic information. Optimal imaging strategies for the pregnant patient should consider performance, safety, patient comfort, availability of the modality, and cost.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Lymphomas have a predilection for abdominal spaces, with splenic involvement classically associated with HL. NHLs such as mantle cell lymphoma may originate in the bowel. Lymphomas in the abdomen and pelvis warrant caution for radiation exposure to a fetus. Diffusion restriction in MR imaging is a useful tool, resulting in increased signal in lymphoma due to its cellularity. WB-MRI, although safe and with performance similar to PET/CT, is susceptible to cardiac motion artifact, which is more pronounced during pregnancy, obscuring hilar involvement. Identifying metabolic activity from FDG-avidity with PET/MRI can herald a worse prognosis, and repeated PET scans encroach on limits for cumulative radioactive FDG uptake by fetus.

Lymphoma in pregnancy is an understudied topic. Optimal imaging practices should consider performance, safety, availability, and cost. PET/MRI and WB-MRI have demonstrated equal or greater performance to PET/CT in nonpregnant patients, with radiation reduction. Investigation of imaging practices in pregnant women with lymphoma to determine optimal imaging modalities and practices are urgently called for.