Transmission of human herpesvirus-8 through liver transplantation and development of post-transplantation Kaposi sarcoma: A case report.

Kaposi sarcoma is a vascular tumour associated with human herpesvirus-8 (HHV-8) infection. Due to immunosuppressive treatment, solid organ transplant recipients infected with HHV-8 have increased risk of Kaposi sarcoma. The risk of being infected with HHV-8 is associated with higher age, male sex, non-White ethnicity, being a man who has sex with men (MSM) and use of recreational drugs. Post-transplant Kaposi sarcoma is rare in HHV-8 low-prevalence areas. We report the first case of a liver transplant recipient developing Kaposi sarcoma following donor-transmitted HHV-8 infection in Denmark. A 51-year-old male underwent uncomplicated liver transplantation at Copenhagen University Hospital - Rigshospitalet, and received standard immunosuppressive treatment with tacrolimus, mycophenolate mofetil and prednisolone. Five months post-transplantation the patient was admitted with abdominal pain, diarrhoea, and dehydration. Ultrasound imaging and PET/CT scan revealed multiple liver tumours. Biopsy from liver tumour diagnosed visceral post-transplantation Kaposi sarcoma. Kaposi sarcoma was successfully treated with reduction of immunosuppressive treatment and conversion from tacrolimus to everolimus, resulting in viral clearance and complete metabolic and structural tumour response. A review of the donor post-transplantation revealed multiple risk factors for being infected with HHV-8, with subsequent analysis confirming the donor was positive for HHV-8. Even in low-prevalence areas, there are benefits of targeted screening for HHV-8 in high-risk organ donors and recipients described in the literature and highlighted in the current case. Post-transplantation Kaposi sarcoma due to HHV-8 may be managed with reduction in immunosuppressive treatment and conversion from calcineurin inhibitors to mTOR inhibitors.