Merkel-Zell-Karzinom nach Nierentransplantation

Merkel cell carcinoma in organ‐transplant recipients: report of two cases with unusual histological features and literature review

“…Up till now, 67 MCC cases have been reported in OTR (Table 3). 11–33 The Israel Penn International Transplant Tumor Registry (1968–2000) contains epidemiological data on 48 MCC that developed in 45 OTR; 12,21 in this registry, MCC accounted for 0.9% of all skin tumors developing in OTR 21 . In the series of 2340 OTR followed in our department, we have diagnosed over 1000 NMSC for just two MCC.…”

“…It has been postulated that this finding suggests an origin from epidermal (Merkel) cells, 38,40 a contention also upheld by the case of purely intraepidermal MCC 42 . In one study, it was found that epidermotropic MCC cells expressed a slightly different immunophenotype compared with their dermal counterparts, and the view was therefore expressed that the former are less differentiated than the latter 32 . Consistent with this finding, we observed that in our second case, in the epidermis, tumor cells forming Pautrier‐like microabscesses in the epidermis showed weaker expression of keratin 20 as compared with dermal tumor cells.…”

“…Although the cause of MCC is not precisely known, immunosuppression seems to be a predisposing factor, since several cases have been observed in the setting of immunosuppression, including HIV infection, 5–7 leukemias, 8–10 and organ transplantation. Up to date, 67 MCC cases have been reported, mostly briefly, in OTR 11–33 . The percentage of patients with MCC with organ transplants is unexpectedly large (7–8%), so that the incidence of MCC in OTR seems increased as compared with the general population 12,21 .…”