Molecular evidence of parvovirus B19 in the cutaneous polyarteritis nodosa tissue from a patient with parvovirus-associated hemophagocytic syndrome: Case report.

Rationale: Parvovirus B19 has been linked to polyarteritis nodosa (PAN), but there is some controversy about its pathogenesis regarding whether it is triggered by the immune complex or by the activated immune cells that phagocytose viruses. Patient concerns: A 38-year-old woman was admitted with fever and bicytopenia. She also complained of a painful palpable nodule in the left forearm. Diagnosis: Her bone marrow aspirate revealed erythroblasts in abnormal megaloblastic changes, some of which presented with pseudopods, and parvovirus B19 was positive in a PCR analysis of her blood, which was compatible with parvovirus B19-induced hemophagocytic syndrome. Skin excisional biopsy of the nodule on the left forearm revealed a heavy inflammatory cell infiltrate throughout whole layers of a medium-sized vessel, the characteristic feature of PAN. PCR analysis of the vasculitis tissue showed a positive result for parvovirus B19. Interventions: Her symptoms spontaneously resolved with supportive care. Outcomes: She underwent regular follow-up without recurrence of vasculitis-associated symptoms. Lessons: This case highlights the presence of parvovirus B19 DNA in vasculitis tissues, which can support the role of cellular immune response in the pathogenesis of parvovirus-associated PAN.