A dramatic response to checkpoint inhibitor in a woman with small cell carcinoma of the hypercalcemic type of the ovary

We present the rare case of a 21 year old woman with small cell carcinoma of the right ovary of the hypercalcemic type with dramatic response to checkpoint inhibitor. Case report. Our patient, a 22-year old woman with small cell carcinoma of the hypercalcemic type with hepatic metastases, is currently 43 months under treatment with pembrolizumab. Last MRI revealed no viable liver metastases nor other signs of recurrence. This is the longest survival of a patient with small cell carcinoma of the ovary under therapy with checkpoint inhibitors reported in the literature so far. With this report we emphasize the importance of immunohistological testing for PD-L 1. Treating clinicians should keep off-label use of immune checkpoint blockade in mind when treating this highly aggressive tumor if all other treatment options fail. •This is the longest survival of a patient with SCCOHT under therapy with checkpoint inhibitors reported in the literature.•This report emphasizes the importance of immunohistological testing for PD-L 1.•Clinicians should consider off-label use of immune checkpoint blockade when treating this highly aggressive tumor.