Background: Merkel cell carcinoma (MCC) is a rare skin neoplasm first described by Toker in 1972. The
tumor usually presents in the sixth to seventh decade of life as a solitary reddish-brown to violaceous
subcutaneous nodule on the head, neck, or the extremities. It is seen at an earlier age only in
immunocompromised patients like transplant patients in immunosuppressive therapy. Thus, cancer has now
become the second cause of death among transplant patients. The tumor growth is rapid in MCC patients,
and for metastatic disease, no substantial benefit is obtained by chemotherapy. A new drug has recently
become available, an immune checkpoint inhibitor (CPI), avelumab, that is able to delay disease progression
significantly. However, there are no current guidelines for the use of immune checkpoint inhibitors in
transplant patients.
Case Presentation: We describe the case of a 55-year-old kidney transplant patient on immunosuppressive
therapy with tacrolimus with an early occurrence of a Merkel cell carcinoma whose aggressive behaviour
could not be hampered by Avelumab, due to fear of allograft rejection.
Conclusion: CPI therapy is potentially lifesaving in advanced MCC. Further studies are urgently needed to
test its benefit in this rapidly expanding field of post-transplant malignancies where there are only a few and
less effective therapeutic options.
Immune checkpoint inhibitor therapy in HIV-associated Merkel cell carcinoma: A case series of 3 patients
