Abstract
VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is an autoinflammatory illness that arises due to inactivating mutations in the X-linked UBA1 gene and progresses to impaired ubiquitination, accumulation of misfolded proteins, and activation of numerous inflammatory pathways. Several reactive conditions may mimic the clinical and morphological findings of VEXAS syndrome; therefore, careful differentiation from more common diseases is essential. We present an 82-year-old female who had clinical and morphological features suggestive of VEXAS syndrome; however, a diagnosis of VEXAS syndrome was ruled out since a pathogenic UBA1 gene mutation was not found. Further evaluation established a final diagnosis of megaloblastic anemia with masked macrocytosis, which closely simulated the hematological manifestations of VEXAS syndrome. This case study emphasizes how challenging it is to diagnose VEXAS syndrome mimickers and how crucial it is to do a systematic clinical and laboratory assessment in order to distinguish it from other common illnesses with uncommon presentations.