Abdominal involvement in Erdheim-Chester disease (ECD): MRI and CT imaging findings and their association with BRAF^V600E mutation.

Abstract

To use magnetic resonance imaging (MRI) and computed tomography (CT) to define abdominal involvement in Erdheim-Chester disease (ECD), and to investigate the association between these findings and the BRAF^V600E mutation. This prospective study was performed on 61 ECD patients (46 men). The MRI and CT imaging studies were reviewed independently by two experienced radiologists. The association between BRAF^V600E mutation and imaging findings was analysed using Fisher's exact test, and odds ratios with 95% confidence intervals. Perinephric infiltration was the most common finding (67%), followed by involvement of proximal ureters (61%). In 56% of cases, infiltration extended to the renal sinuses, and in 38% caused hydronephrosis. Adrenal gland infiltration was present in 48% of patients. Infiltration of renal artery (49%) and aorta (43%) were the most common vascular findings, followed by sheathing of celiac, superior mesenteric artery (SMA) or inferior mesenteric artery (IMA) (23%). The BRAF^V600E mutation was positive in 53% of patients with interpretable BRAF sequencing. There was a statistically significant association between this mutation and perinephric infiltration (p = 0.003), renal sinus involvement (p < 0.001), infiltration of proximal ureters (p < 0.001), hydronephrosis (p < 0.001), adrenal gland involvement (p < 0.001), periaortic infiltration (p = 0.03), sheathing or stenosis of renal artery (p < 0.001) and sheathing of other aortic branches (p = 0.04). Renal and vascular structures are the most commonly affected abdominal organs in ECD patients. Some of these findings have significant positive association with the BRAF^V600E mutation. • Abdominal imaging plays a crucial role in management of Erdheim-Chester disease. • Significant associations exist between BRAF ^V600E mutation and several abdominal imaging findings. • Considering several associations, evaluating BRAF^V600E mutation status is recommended in ECD patients.