Leukocytoclastic vasculitis associated with hairy cell leukemia at diagnosis: a case report and review of the literature.

Background: Autoimmune manifestations may occur in patients with hairy cell leukemia (HCL), and some rare cases of polyarteritis nodosa and leukocytoclastic vasculitis have been reported. However, data regarding the treatment of these cutaneous manifestations are lacking, given the rarity of the concomitance of HCL and vasculitic syndromes.

Case Presentation: We present a 37-year-old man with paraneoplastic leukocytoclastic vasculitis complicating newly diagnosed HCL. The vasculitis completely resolved after the first 3 weekly administrations of cladribine, which is regarded as the gold-standard treatment for this disease. The underlying leukemia showed refractoriness to the same agent, thus requiring a second line of treatment.

Conclusions: The clinical picture we have observed is of interest for the following reasons: i) it confirms an existing pathogenetic relationship between this lymphoproliferative disorder and its cutaneous manifestations, as suggested by the prompt resolution of the purpuric lesions upon cladribine administration; ii) it indicates that cladribine is an effective treatment for HCL-related paraneoplastic syndromes, including leukocytoclastic vasculitis; iii) the evolution and the outcomes of the paraneoplastic manifestations may be independent of those of the underlying leukemia, which showed less than a partial response to its initial treatment.