Disseminated Rhodococcus equi infection in a patient with diffuse large B-cell lymphoma treated with immunotherapy

Immunotherapies can lead to an immune compromised state that can allow for opportunistic pathogens such as Rhodococcus to flourish. The vast majority of Rhodococcus infections occur in immunocompromised hosts. Here we describe disseminated Rhodococcus equi infection in a patient with diffuse large B-cell lymphoma treated with immunotherapy. Infection with Rhodococcus can be diagnosed with the aid of cytomorphology and histochemical findings and the organism confirmed by sequencing. In conclusion, Rhodococcus should be considered in the differential of granulomatous inflammation in immunocompromised individuals treated with immunotherapies.