An unusual case of invasive pleuritis and miliary Mycoplasma pneumonia during check-point inhibitor therapy.

A growing body of evidence suggests that check-point inhibitors not only increase the overall risk of infections, but, due to an altered immune response, may also result in atypical manifestations. We report a case of a 38-year-old man with pleuritic chest pain, dyspnoea, fevers and a dry cough receiving combination ipilimumab and nivolumab immunotherapy for metastatic melanoma. Radiological findings demonstrated a diffuse increased fluorodeoxyglucose avidity of the thoracic pleura in addition to a disseminated miliary pattern of pulmonary nodularities. A subsequent bronchoscopy was macroscopically normal with unremarkable washings. In the context of a significantly elevated Mycoplasma serology, a diagnosis of Mycoplasma pneumoniae pneumonia (MPP) was made. The patient was successfully treated with a course of azithromycin and amoxicillin-clavulanic acid. We suggest an awareness of diffuse pleuritis and a disseminated miliary nodular pattern as atypical manifestations of MPP, potentially attributable to immune modulation in the context of immunotherapy.