Skin cancer multiplicity is common in KTR. Patients with a first skin cancer are at increased risk for more skin cancers and need to be carefully checked for subsequent skin cancers.

Summary Background  Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is rare. Guidelines for staging, treatment and follow‐up are lacking. Objectives  To better define staging procedures, treatment results and clinical course in adult patients with LCH first presenting in the skin. Methods  Eighteen adult patients with LCH first presenting in the skin were collected from five centres collaborating in the Dutch Cutaneous Lymphoma Group. Clinical records and (skin) biopsy specimens were reviewed and follow‐up data were obtained. A literature search on adult patients with LCH presenting in the skin was performed. Results  Staging procedures showed extracutaneous disease in three of 16 patients who were adequately staged. One patient had a histologically confirmed lytic LCH bone lesion, while two patients had a myelodysplastic syndrome. During follow‐up two of 18 patients developed extracutaneous localizations of LCH. Five patients developed a second haematological malignancy, including (myelo)monocytic leukaemia (two cases), histiocytic sarcoma (one case), diffuse large B‐cell lymphoma (one case) and peripheral T‐cell lymphoma (one case). Review of the literature revealed six other adult patients with a second haematological malignancy preceding or following a diagnosis of LCH. Conclusions  The results of the present study suggest an increased risk of a second haematological malignancy in adult patients with LCH presenting in the skin. Extensive staging at presentation and long‐term follow‐up are therefore warranted in such patients.

This study gives a systematic overview of the high burden of skin diseases in OTRs. The relative distributions of skin diseases importantly changed with time after transplantation, with squamous cell carcinoma contributing most to the increasing burden of skin diseases with increasing time after transplantation.