Merkel cell carcinoma in kidney transplant recipients in Ireland 1964–2018

Funding sources: none. Conflicts of interest: none to declare. Dear Editor, Merkel cell carcinoma (MCC), an aggressive neuroendocrine carcinoma, typically occurs in fair‐skinned male patients, on sun‐exposed skin. Although rare, from 2000 to 2013, a 95% increase in incidence in MCC has been documented with further increases projected.1 There is a paucity of data pertaining to the epidemiology of MCC in organ transplant recipients (OTR). Therefore, we describe the national experience of MCC in kidney transplant recipients (KTR) in Ireland. The Irish National Kidney Transplant Service (NKTS) registry was reviewed for cases of MCC from 31 March 1964 to 1 April 2018. Pathology and clinical records, pertaining to the cases of MCC identified from the NKTS, were reviewed to establish additional pertinent clinical information. In order to characterize the standardized incidence ratio (SIR) of MCC, this data was also linked with the National Cancer Registry of Ireland data from 1 January 1994 to 31 December 2014. The SIR for MCC was calculated in comparison with the general population using Irish national census data as the denominator, and using International Classification of Diseases (ICD)‐10 coding for MCC diagnosis.