Merkel cell carcinoma in renal transplant recipient.

SUMMARY – A 57-year-old male was started on hemodialysis in 1998 because of end-stage renal disease caused by IgA nephropathy. He received an allograft in April 2002 and was treated with cyclosporine, mycophenolate mofetil and steroids. Graft function was optimal, without episodes of acute rejection. A red intradermal painless nodule was observed in the left preauricular region in September 2004. Immunohistochemical staining showed perinuclear expression of cytokeratin 20 and synaptophysin as well as the presence of neuron-specific enolase and chromogranin, characteristic of Merkel cell carcinoma. Radical re-excision with a median margin of 2 cm was necessary. The patient received adjuvant radiotherapy in a total dose of 55 Gy in 20 cycles. Immunosuppressive therapy was reduced. Merkel cell carcinoma is a rare aggressive cancer that may be misdiagnosed as an indolent skin disease. In immunocompromised host it is more likely to occur, at a younger age and probably assuming a more aggressive course than in the general population.