PURPOSE: The incidence of malignancies after an organ transplant has steadily increased along with a significant improvement of the long-term recipient survival. Eighty-seven variable post-transplant malignancies out of 2,140 renal transplantations were encountered at Yonsei University Medical Center. Among them, we recently experienced a Merkel cell carcinoma (MCC), a rare malignancy originates from neuro-endocrine cells. Herein, we report 6 MCC cases in cluding 5 that developed in non-transplant patients. METHODS: The medical records of 6 patients who have been diagnosed with a MCC since 1984 were reviewed. RESULTS: There were four males and two females. The mean age at the time of diagnosis was 57.7 (48-65). Five cases were a primary MCC and one was secondary in nature that was related to long-term immunosuppression after a kidney transplant. The extremities (n=3), the head and the neck (n=2) were the prevalent sites for MCC. Four patients are currently alive after mean follow-up of 33.3 months (2-67). The secondary case was a MCC that developed in a 49 years old male patient 16 years after receiving a living donor renal transplant. He noticed a mass on the antero-lateral side of the left thigh 1 month before admission. The mass was soft, round, red-violet in color and measured 5 cm in diameter. With 5 mm of skin margin, the mass was completely excised and was found to be a MCC. To rule out loco-regional and distant metastasis, thoraco-abdomino-pelvic CT scan was taken which showed no evidence of abnormal images. Considering the aggressive biological nature of the MCC, we radically excised more skin and muscular ascia, but no remnant malignant cells were found by pathology. CONCLUSION: MCC presents as a dermal mass mostly at the head, neck, and the extremities with characteristics of rapid aggressive metastasis and recurrence. Wide excision with a 3 cm margin is recommended in patients without a meta stasis. This is the first report of a MCC after a renal transplantat in Korea.
Academic Medical Centers ; Carcinoma, Merkel Cell* ; Diagnosis ; Extremities ; Female ; Follow-Up Studies ; Head ; Humans ; Immunosuppression ; Incidence ; Kidney ; Kidney Transplantation ; Korea ; Living Donors ; Male ; Medical Records ; Middle Aged ; Neck ; Neoplasm Metastasis ; Pathology ; Recurrence ; Skin ; Thigh ; Tomography, X-Ray Computed ; Transplants