Additionally, the most common histologic findings include leukocytoclastic vasculitis, neutrophilic dermatosis, and perivascular dermatitis; different variants in the UBA1 gene are associated with specific skin manifestations.
Those are key findings from a cohort study of 112 patients with VEXAS published online in JAMA Dermatology. The study, conducted by researchers at the National Institutes of Health (NIH) and several other institutions, aimed to define the spectrum of cutaneous manifestations in VEXAS in association with genetic, histologic, and other clinical findings.
Edward W. Cowen, MD, MHSc
Dr. Edward W. Cowen
First described in 2020, VEXAS syndrome is an adult-onset multisystem disease that can pose a diagnostic challenge to clinicians, the study’s corresponding author, Edward W. Cowen, MD, MHSc, of the dermatology branch at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), said in an interview. The disease is caused by pathogenic variants in the UBA1 gene, located on the X chromosome. Affected individuals exhibit a wide range of manifestations, including cytopenia/myelodysplasia, multiorgan systemic inflammation, and cutaneous involvement.
“Patients may present to a variety of disease specialists depending on their symptoms and providers may not immediately consider a genetic etiology in an older individual,” Dr. Cowen said in an interview. “Although skin involvement occurs in more than 80% of patients, it is pleomorphic and may resemble a variety of other conditions such as vasculitis and Sweet syndrome.”
To better understand the cutaneous manifestations of VEXAS syndrome, the researchers evaluated data from 112 patients with VEXAS-defining genetic variants in the UBA1 gene between 2019 and 2023. Of the 112 patients, 73 underwent medical record review only, and 39 were prospectively evaluated at NIH. All but one of the patients were men, 94% were White individuals, and their mean age was 64 years. Skin involvement occurred in 83% of cases and was the most common presenting feature of VEXAS in 61% of cases.
Of the 64 histopathologic reports available from 60 patients, the main skin histopathologic findings were leukocytoclastic vasculitis in 23 patients (36%), neutrophilic dermatosis in 22 patients (34%), and perivascular dermatitis in 19 patients (30%). According to Dr. Cowen, one key histologic finding was a distinct pattern of “histiocytoid” dermal neutrophilic inflammation, which was present in 13 of 15 specimens (86%) that underwent central re-review. “This pattern can occasionally also be seen in patients with Sweet syndrome, unrelated to VEXAS, but was a hallmark feature found in the majority of skin biopsies of patients with VEXAS,” he said.
Image courtesy of JAMA Network
Examples of skin manifestations of VEXAS syndrome
“Together with another pathologic finding, leukocytoclasia, these features can be useful clues to alert the pathologist to a potential diagnosis of VEXAS. This myeloid predominant pattern of skin inflammation was also most strongly associated with the leucine pathogenic variant of the UBA1 gene.” In contrast, cutaneous vasculitis was most strongly associated with the valine pathogenic variant of UBA1. “This is important because the valine variant has been previously independently linked to decreased survival,” he said.
In findings related to pathogenic genetic variants, the researchers observed that the p.Met41Leu variant was most frequently associated with neutrophilic dermal infiltrates in 14 of 17 patients (82%) with this variant and often resembled histiocytoid Sweet syndrome. In addition, the p.Met41Val variant was associated with vasculitic lesions in 11 of 20 patients (55%) with this variant and with a mixed leukocytic infiltrate in 17 of these 20 patients (85%).