Erdheim-Chester disease (ECD) is a rare potentially fatal hematopoietic neoplasm of histiocytic origin occurring mainly in adults. ECD can affect several organs (Figure 1) including the adrenal glands [1]. ECD diagnosis relies upon clinical, laboratory, histologic, and radiologic studies. There is no established therapy for ECD with empiric treatments including antiinflammatory, immunosuppressive, and chemotherapeutic agents Recent data shows that the majority of ECD patients harbor BRAF V600E and MAPK pathway gene mutations, initiating treatment strategieswith BRAF and MEK inhibitors [2].The estimated ECD mortality rate is...

Prospective evaluation of 15 ECD patients (mean age at first ECD manifestations: 53y.o.) with whole body 18F-FDGPET/CT scans. 11 patients were BRAF-positive, 4 were BRAF-negative, while in 1 patient the mutation status was not tested. Adrenal metabolic activity was assessed by quantifying 18F-FDG uptake, using the MIM Vista workstation (version 6.5.9). A VOI encompassing both adrenal glands was drawn, and an automated SUV threshold-based approach was applied in order to include all 18F-FDG avid adrenal regions, while excluding low level background activity. The applied framework...

Mann Whitney test showed statistically significant differences (p<0.05) in TV and TGA values between BRAF-positive and BRAF-negative ECD patients, with mutation carriers presenting higher mean TV (11.33 vs 3.2) and TGA values (29.3 vs 7.58) respectively.

ECD patients harboring the BRAF V600E mutation present hypermetabolic adrenal glands when compared to mutation negative counterparts, suggesting susceptibility to adrenal involvement and potentially adrenal insufficiency.

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