Objectives Donor-transmitted malignancies are rare due to the strict selection criteria for donors. Diagnosis is challenging because they often have an atypical presentation and a poor response to treatment.

Methods We present the case of a woman who was diagnosed with a donor-transmitted carcinoma after kidney transplantation.

Results Two years after kidney transplantation, a 61-year-old woman was diagnosed with a FIGO stage IIIB Mullerian ovarian cancer. Treatment with neo-adjuvant chemotherapy was started and complicated due to the use of immunosuppressants. An interval-debulking procedure showed poor response to chemotherapy and an optimal debulking could not be achieved. Pathology revealed a high grade tumor with immunohistochemistry suggestive for lung carcinoma. However, a PET-CT did not indicate any pulmonary disease. Due to the atypical presentation, immunohistochemistry results and untraceable primary tumor additional genetic DNA profiling was performed to further investigate the origin. A Y-chromosome specific marker revealed that the tumor originated from the donor-transplant. The oncological treatment and immunosuppressants were discontinued. The kidney transplant was surgically removed and hemodialysis was initiated. The body’s own immune response led to a clinical, biochemical and radiological complete response and patient has no evidence of disease after 1 year of follow-up.

Conclusions This case report illustrates the diagnostic and therapeutic challenges of cancer in transplant-patients. We suggest that DNA profiling should be standard procedure in transplant patients presenting with metastatic disease. Although donor-transmitted malignancies are a very rare finding, awareness is critical since it can have life-saving clinical implications.