Atypical hypersensitivity to mosquito bites without natural killer cell proliferative disease in an adult patient.

Hypersensitivity to mosquito bites (HMB) is a rare disorder that occurs in the first 2 decades of life and is considered to be associated with chronic Epstein-Barr virus (EBV) infection and natural killer (NK) cell leukemia/lymphoma. EBV-encoded small nuclear RNA (EBER)-positive NK cells infiltrate the skin lesion at the site of the mosquito bite. In this report, we present the case of an adult patient with mantle cell lymphoma complicated by atypical HMB. The anti-EBV antibody titer of the patient indicated reactivation of chronic infection with this virus, and EBV DNA in the peripheral blood mononuclear cells was detected after chemotherapy by quantitative polymerase chain reaction analysis. However, an in situ hybridization analysis did not detect EBER-positive cells in the skin lesion at the bite site or in the lymph node. Peripheral NK cell lymphocytosis and EBV-associated lymphoproliferative disease did not develop. These findings suggest that some patients with chronic EBV infection may develop HMB without NK cell proliferative disease.