Merkel Cell Carcinoma in Solid Organ Transplant Recipients

Abstract

As a result of lifelong immunosuppression, solid organ transplant recipients (SOTRs) have decreased immune surveillance and therefore are at increased risk of developing cutaneous malignancies. This chapter reviews the literature on less commonly encountered cutaneous neoplasms in SOTRs, including Kaposi’s sarcoma (KS), sebaceous carcinoma, atypical fibroxanthoma (AFX), and dermatofibrosarcoma protuberans (DFSP). Because of the low incidence and prevalence of these tumors, much of the information is compiled from published case reports and summaries of cases. KS is a tumor of endothelial cell origin related to human herpesvirus 8 infection. It presents as multiple purplish, reddish-blue nodules and plaques mainly on the lower extremities but can also involve the mucosa and viscera. Management involves reduction of immunosuppression, although additional local or systemic treatments are often required. Sebaceous carcinoma, which may or may not be related to underlying Muir-Torre Syndrome, tends to present in extraorbital locations in SOTRS and is most often treated surgically. AFX is a spindle cell neoplasm seen in sun-exposed areas, predominantly in men, and is also commonly treated surgically. DFSP is extremely rarely reported in SOTRs. Its clinical presentation and management are similar as those of DFSP in immunocompetent patients. Despite the low frequency of these cutaneous malignancies in SOTRs, they still need to be considered in the differential diagnosis of new cutaneous lesions. When making management decisions, it is important to consider immunosuppressive medications and the specific transplanted allograft.