Yellow nail syndrome after allogeneic haematopoietic stem cell transplantation in two patients with multiple myeloma.

OBJECTIVE AND IMPORTANCE: Yellow nail syndrome (YNS) is a rare disorder of unknown aetiology characterized by the triad of yellow nails, lymphoedema and respiratory manifestations. About 200 cases have been reported, but a lot of patients probably elude proper diagnosis because of both variability of symptoms and ignorance of this syndrome by many physicians. The pathogenesis remains unclear, and could involve functional lymphatic abnormalities, microvasculopathy or lymphocyte deficiency, but none of these hypotheses seems fully satisfactory. CLINICAL PRESENTATION: We report for the first time two cases of YNS associated with multiple myeloma relapsing after non-myeloablative haematopoietic cell transplantation (HCT). In these two cases, onset or worsening of YNS symptoms followed graft-versus-host disease (GvHD) manifestations. INTERVENTION: Corticosteroids given to treat GvHD also improved YNS manifestations. CONCLUSION: YNS after HCT might be a microvascular manifestation of endothelial GvHD and corticosteroids might be an effective treatment.