Anaplastic Large Cell T Cell Lymphoma in a Patient With Severe Therapy-refractory Crohn's Disease on Long-standing Immunosuppressive Medication During Ustekinumab Treatment: A Case Report and Review of the Literature

Use of ustekinumab in Crohn's disease was approved in 2016, and consequently data regarding its real-world safety are still limited. We here present a 29-year-old woman with severe therapy-refractory Crohn's disease, who developed an anaplastic large cell T cell lymphoma during treatment with ustekinumab.