Melanomas in renal transplant recipients.

Background: It is well documented that renal transplant recipients are at increased risk of developing skin cancers, in particular squamous cell carcinomas. Less extensively reviewed in the literature is the increased incidence of malignant melanoma. We have reviewed 10 patients in the Oxford renal transplant population who developed 12 melanomas following transplantation.

Objectives: To determine the incidence and characteristics of melanoma in renal transplant recipients.

Methods: We reviewed the case notes and pathology of all patients who developed melanoma within the Oxford Renal Transplant Unit. The clinical details were recorded including date of transplant, immunosuppressive therapy, interval between transplant and melanoma, site of occurrence, history of sun exposure, type of clinician diagnosing the melanoma, history of other skin malignancies and outcome. From the histopathology we documented various prognostic factors.

Results: Ten patients developed 12 melanomas (one patient had three melanomas) from a population of 1874 transplanted patients. The total number of transplant years was 11 942.2. The incidence of melanoma in our population was 12 per 11 942.2 transplant years, which is approximately 8 times greater than the standardized rate for this region. We found that the mean interval between transplant and melanoma was approximately 11 years (median 8.5). A dermatologist was the diagnosing clinician in at least 67% of cases. Melanomas occurred on the trunk in the majority of cases (58%), followed by the upper limb (25%). All patients apart from one are alive with no recurrence of their melanoma. One patient died as a result of metastatic melanoma. The mean follow-up period following melanoma was 3.7 years. In all patients apart from the patient who died, the melanomas were < 1 mm Breslow thickness. That patient's melanoma was 4.5 mm thick. There was no precursor naevus in eight of the 12 melanomas. In two there was a precursor dysplastic naevus. In the cases in vertical growth phase the tumour-infiltrating lymphocyte response was absent in four cases and nonbrisk in one patient.

Conclusions: In the Oxford transplant population studied melanomas occurred at approximately 8 times the rate in the general population. This is the highest rate reported in the literature. The patients had a better outcome than reported previously. This may be due to detection at a relatively early stage. Renal transplant recipients attend dedicated dermatology clinics in Oxford, which may have contributed to the early diagnosis and good outcome.