BackgroundAtypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are increasingly common sarcomas of the skin with a genetic UV signature. Immunosuppression is a known risk factor for developing other UV-induced skin cancers such as cutaneous squamous cell carcinoma (cSCC), basal cell carcinoma (BCC), and Merkel cell carcinoma with increased mortality. In case reports or small case series of AFX/PDS patients, immunosuppression has been hypothesized as a risk factor for the development of distant metastases. The aim of the present study was to analyze immunosuppression as a risk factor for AFX/PDS in a large patient cohort.MethodsA cohort of 164 patients with AFX/PDS (47 AFX and 117 PDS) was collected between 2003 and 2021 and analyzed for clinicopathological data with a special focus on immunosuppression.ResultsOf all patients, 29.9% had any kind of immunosuppression; 6.4% of the AFX and 12.0% of the PDS patients had underlying hemato-oncological diseases. Patients with immunosuppression due to an underlying hemato-oncological disease had a significantly increased risk of progressing to (p = 0.010) and developing distant organ metastases (p = 0.000).ConclusionsImmunosuppression seems to be a risk factor for developing AFX/PDS with worse clinical outcomes. Therefore, immunosuppression, especially underlying hemato-oncological diseases, should be considered in the treatment and follow-up care of patients with AFX/PDS.