Kaposi's sarcoma triggered by endogenous HHV-8 reactivation after non-myeloablative allogeneic haematopoietic transplantation.

Human herpesvirus 8 (HHV-8) is causally associated with Kaposi's sarcoma (KS). KS is most frequently observed in HIV patients and in solid organ transplant recipients. The role of HHV-8 in allogeneic haematopoietic cell transplantation (HCT) remains to be determined. Here we describe a case in which KS concomitantly occurred with CMV reactivation after a non-myeloablative allogeneic HCT and presented with skin lesions, but not visceral involvement. Skin biopsy confirmed the diagnosis and ruled out graft versus host disease or disease recurrence. Molecular findings indicated viral reactivation of the recipient's primary infection. Tumour lesions completely receded when immunosuppression was tapered. Prevalence studies in donors and recipients are needed to determine the clinical impact of HHV-8 in HCT.