A case of autosplenectomy associated with T-cell checkpoint inhibitor treatment.

Delahunty R, et al. BMJ Case Rep 2017. doi:10.1136/bcr-2017-220775 Description A 77-year-old Caucasian man presented to the oncology service with de novo v-raf murine sarcoma viral oncogene homolog B (BRAF), wild-type metastatic melanoma and widespread disease involving; subcutaneous fat, lymph nodes, bone and spleen with no history of autoimmunity. At diagnosis, the spleen was measured within normal limits on CT. In November 2013, he commenced treatment on a phase-III randomised double-blinded clinical trial (CA209-067) and received combination checkpoint inhibitor therapy with ipilimumab and nivolumab. Radiological mixed response was observed after three months, with a partial response in all target lesions (RECIST V.1.1 criteria) but an increase in the size of the non-target splenic metastasis consistent with pseudoprogression. In conjunction, splenic enlargement was demonstrated (figure 1). After seven months of immunotherapy, he achieved a complete radiological response to treatment with an accompanying reduction in splenic size (figure 2). Subsequent imaging demonstrated a persistent reduction in splenic size and by June 2015, only a spleen remnant remained (figure 3). Functional hyposplenism was demonstrated with Howell-Jolly bodies and Acanthocytes on the peripheral blood film (figure 4). His treatment was complicated by a range of immune-related adverse events (irAE) including hypophysitis, nephritis and colitis.Although steroid dependant, he remains in radiological remission with an excellent performance status. In the absence of alternative autoimmune pathology, we hypothesise that this is a case of checkpoint inhibitor-induced autosplenectomy, the first reported case of a new rare irAE.