PT  - JOURNAL ARTICLE
AU  - Jason R. Young
AU  - Geoffrey B. Johnson
AU  - Robert C. Murphy
AU  - Ronald S. Go
AU  - Stephen M. Broski
TI  - &lt;sup&gt;18&lt;/sup&gt;F-FDG PET/CT in Erdheim–Chester Disease: Imaging Findings and Potential BRAF Mutation Biomarker
AID  - 10.2967/jnumed.117.200741
DP  - 2018 May 01
TA  - Journal of Nuclear Medicine
PG  - 774--779
VI  - 59
IP  - 5
4099  - http://jnm.snmjournals.org/content/59/5/774.short
4100  - http://jnm.snmjournals.org/content/59/5/774.full
SO  - J Nucl Med2018 May 01; 59
AB  - The purpose of this study was to evaluate 18F-FDG PET/CT for the diagnosis, management, and treatment of Erdheim–Chester disease (ECD). Methods: Our institutional database (2007–2017) was retrospectively reviewed for patients with pathologically proven ECD. A chart review yielded demographics, clinical information, and 5 categories of clinical impact. Two radiologists in consensus interpreted the images. Imaging findings were correlated with clinical data. Results: Seventy-one 18F-FDG PET/CT examinations were performed for 32 patients. The average SUVmax of the most active disease site was 9.2 (SD, 6.1). The most common sites involved were the skeleton (90.6% of patients, including 47% with axial and pelvic skeletal involvement), kidneys (81.3%), and central nervous system (CNS) (46.9%). Twenty-six patients were tested for a proto-oncogene B-Raf V600E (BRAF) mutation (18 had the mutation and 8 did not). The presence of a BRAF mutation was associated with 18F-FDG–avid CNS disease (P = 0.0357), higher SUVmax (P = 0.0044), and greater mortality (P = 0.0215). The presence of CNS disease had 88% specificity and a 92% positive predictive value for predicting the presence of a BRAF mutation. PET/CT examination results influenced patient management in 48% of cases (34/71). Conclusion: 18F-FDG PET/CT results may act as a biomarker for the presence of a BRAF mutation, aid in establishing a diagnosis, guide biopsies, and gauge the treatment response in ECD patients. Axial and pelvic skeletal involvement is greater than previously reported.