Late-onset pericardial tamponade, bilateral pleural effusions and recurrent immune monoarthritis induced by ipilimumab use for metastatic melanoma.

While an important agent in the contemporary anti-melanoma armamentarium, ipilimumab is associated with serious immune reactions including late immune-mediated side effects. Recently, a case of late-onset acute pericarditis with tamponade was reported at 12 weeks after the last dose of ipilimumab. While polyarthralgia rheumatica has been previously documented with ipilimumab, we were not able to find any reports of recurrent monoarthritis with the use of this agent. Therefore, we present herein a unique case featuring a patient with late-onset autoimmune pleuropericarditis leading to cardiac tamponade at 24 weeks post-ipilimumab and recurrent late immune knee arthritis at 8 and 32 weeks, respectively. Furthermore, this late-onset toxicity seen with ipilimumab might also be expected with the PD1 inhibitors currently in clinical use. Timely diagnosis and prompt steroid use are crucial to ensure favorable clinical outcomes in these patients.