Kaposi sarcoma in solid organ transplant recipients: updates in epidemiology, diagnosis, treatment and prevention

Kaposi's sarcoma (KS) is one of the most frequent malignancies observed in solid organ transplant (SOT) recipients, and it is associated with human herpes virus 8/Kaposi's sarcoma-associated herpesvirus (HHV-8/KSHV) infection. The incidence varies according to the prevalence of HHV-8/KSHV in the population, the intensity of the immunosuppression and serological status of organ donor and recipient. Both latent and lytic phases of the HHV-8/KSHV life cycle play crucial role in the pathogenesis, influencing oncogenesis, immune evasion, and inflammasome activation. KS can be the result of reactivation of HHV-8/KSHV latent infection in the immunosuppressed recipient or be the consequence of a primary infection (either donor- or non-donor-derived), the latter possibly associated with a more aggressive clinical course. KS usually presents with cutaneous lesions, however post-transplant KS is characterized by visceral and/or lymph node involvement, frequently in absence of cutaneous lesions, underlying the challenges associated with KS diagnosis in SOT and the need of high clinician suspicion. The mainstay of post-transplant KS management is reduction of immunosuppression, along with conversion to mTOR inhibitors, while in visceral forms chemotherapy with liposomal doxorubicin is usually the first choice. Active surveillance and personalized management strategies, based on risk stratification and multimodal therapeutic approaches, are essential to optimize outcomes in transplant recipients affected with KS.