CD4/CD8 double-positive adult T cell leukemia with preceding cytomegaloviral gastroenterocolitis.

We present a rare case of adult T cell leukemia (ATL) in which leukemic T cells simultaneously expressed CD4 and CD8 surface antigens and refractory cytomegalovirus (CMV)-induced gastroenterocolitis preceded its clinical onset. A 40-year-old male was admitted to our hospital with abdominal pain and bloody stool. Biopsy specimens of the gastric and rectal mucosa indicated CMV-induced gastroenterocolitis. The patient also proved to be seropositive for human T lymphotropic virus type I (HTLV-I). While being administered gancyclovir for CMV infection, he presented hepatomegaly and systemic lymphadenopathy. Monoclonal expansion of lymphoid cells integrated with HTLV-I genome was observed. He underwent a LSG15 regimen and hepatomegaly and lymphadenopathy improved markedly. Gastroenterocolitis also improved, but the symptoms did not disappear completely. CMV-induced diseases are prevalent among immunosuppressed patients. Although there was no evidence that this patient had ATL on admission, it is likely that he was severely immunodeficient. CMV can easily infect damaged mucosa. ATL cells often infiltrate gastrointestinal mucosa and may have triggered CMV gastroenterocolitis in this case.