34

The observation of vacuoles in hematopoietic cells in a bone marrow aspiration may challenge the cytologist and lead to discussion of their specificity and the value of reporting them. These vacuoles are observed in many pathological situations, of hematological origin or not, and since 2020, their presence has been an argument for putting forward the diagnosis of VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome), linking clonal hematopoiesis and systemic auto-inflammation. We report on 3 patients with VEXAS syndrome in whom repeat myelograms found vacuoles in more than 10% of granular precursors with an average of more than 3 vacuoles per cell. All these cases presented macrocytic anemia and lymphopenia associated, or not, with other cytopenias. They all had a mutation of UBA1. An overview of the current data from the literature is given in order to show the contours of this pathology. The combination of macrocytic anemia, skin lesions, and fever in an autoinflammatory context in a male patient may lead to the suspicion of VEXAS syndrome. A bone marrow aspiration might be done to search for vacuoles in the myeloid precursors as well as for a UBA1 gene mutation. A myelodysplastic syndrome alongside it worsens the prognosis. Cytologists are therefore on the front line when it comes to putting forward this diagnosis by reporting the presence of significant numbers of vacuoles in order to guide the complementary examinations to be performed.