Correlation of MRI signal characteristics of intracranial melanoma metastases with BRAF mutation status

Lasocki, A; McArthur, GA

Author(s): Lasocki, A; McArthur, GA;
Details: Publication Year 2022-10-01,Volume 32,Issue #5,Page 373-378
Journal Title: Melanoma Research
Publication Type: Research article
Abstract: BRAF V600 mutations (BRAF mut ) are associated with more pigmentation in primary melanomas, but data on melanin content of metastases are limited. This study compares signal characteristics of BRAF mut and BRAF-wildtype (BRAF wt ) intracranial melanoma metastases (IMM). MRI brain examinations at first diagnosis of IMM were identified, all performed at 3-Tesla including 1 mm volumetric pre- and postcontrast T1-weighted imaging and susceptibility-weighted imaging (SWI). Individual metastases were assessed by a neuroradiologist, stratified by size (>/=10 mm, 'larger', vs. 2-9 mm, 'small'; up to 10 per group); presence of intrinsic T1-hyperintensity (T1H) and, if present, whether confidently attributable to melanin as opposed to haemorrhage; evidence of haemorrhage; presence of central necrosis. A total of 267 IMM in 73 patients were assessed (87 larger IMM, 180 small). The proportion of larger IMM was similar in both groups (31% BRAF mut and 36% BRAF wt ). In small IMM, MRI evidence of melanin was more common in BRAF mut patients (42% vs. 26%; P = 0.038). Haemorrhage was more common in larger IMM (51%, vs. 20% of small IMM; P < 0.0001), but did not differ based on BRAF status. Central necrosis was more common in larger IMM (44% vs. 7%; P < 0.0001) and in BRAF mut IMM (23% vs. 11%; P = 0.011). In the BRAF mut cohort, central necrosis was more common in patients without previous anti-BRAF therapy (33% vs. 7%; P = 0.0001). T1H attributable to melanin is only slightly more common in BRAF mut IMM than BRAF wt . Higher rates of central necrosis in BRAF mut patients without previous anti-BRAF therapy suggest that anti-BRAF therapy may affect the patterns of IMM growth.
Keywords: *Brain Neoplasms/diagnostic imaging/genetics/secondary; Humans; Magnetic Resonance Imaging; Melanins/genetics; *Melanoma/pathology; Mutation; Necrosis; Proto-Oncogene Proteins B-raf/genetics; *Skin Neoplasms/genetics/pathology
Department(s): Cancer Imaging; Medical Oncology; Laboratory Research
PubMed ID: 35979667
Publisher's Version: https://doi.org/10.1097/CMR.0000000000000847
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2025-01-09 06:52:47

Last Modified: 2025-01-09 06:54:51