Case Report Late Onset Ipilimumab-Induced Pericarditis and Pericardial Effusion: A Rare but Life Threatening Complication Seongseok Yun, 1 Nicole D. Vincelette, 2 Iyad Mansour, 1 Dana Hariri, 3 and Sara Motamed 4 1 Department of Medicine, University of Arizona, Tucson, AZ 85721, USA 2 Molecular Pharmacology and Experimental Terapeutics, Mayo Clinic, Rochester, MN 55905, USA 3 Department of Pathology, University of Arizona, Tucson, AZ 85721, USA 4 Midwestern University, Arizona College of Osteopathic Medicine, Glendale, AZ 85308, USA Correspondence should be addressed to Seongseok Yun; namaska97@gmail.com Received 11 February 2015; Accepted 23 March 2015 Academic Editor: Francesco A. Mauri Copyright © 2015 Seongseok Yun et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Metastatic cutaneous melanoma has poor prognosis with 2-year survival rate of 10–20%. Melanoma cells express various antigens including gp100, melanoma antigen recognized by T cells 1 (MART-1), and tyrosinase, which can induce immune-mediated anticancer response via T cell activation. Cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) is an immune check point molecule that negatively regulates T cell activation and proliferation. Accordingly, recent phase III clinical trials demonstrated signifcant survival beneft with ipilimumab, a human monoclonal antibody (IgG1) that blocks the interaction of CTLA-4 with its ligands. Since the efcacy of ipilimumab depends on T cell activation, it is associated with substantial risk of immune mediated adverse reactions such as colitis, hepatitis, thyroiditis, and hypophysitis. We report the frst case of late onset pericarditis and cardiac tamponade associated with ipilimumab treatment in patient with metastatic cutaneous melanoma. 1. Case Presentation A 59-year-old male patient with no signifcant history of autoimmune disease presented to clinic with bleeding from a mole in the right forearm. Biopsy and mutation testing identifed melanoma with BRAF V600E mutation. PET/CT showed four FDG avid sof tissue nodules in the subcuta- neous tissues of chest and back, abdominal mesentery, and right retroperitoneum. Excisional biopsy from right axillary lymph node was positive for melanin A staining and showed extracapsular invasion, confrming the diagnosis of stage M1c metastatic melanoma. Terefore, patient received 4 cycles of ipilimumab (3 mg/kg) treatment every 3 weeks without sig- nifcant adverse reaction except skin rash on the infusion site. Twelve weeks afer the last cycle of ipilimumab treat- ment, the patient presented to ED with acute onset chest pain and shortness of breath which started 1 day prior to the presentation. Vital sign showed BP 97/55 mmHg, HR 106 beats/min, RR 20 breaths/min, and O 2 saturation 99% while breathing room air and temperature 36.9 ∘ C. Physical examination revealed distant heart sound and 5 cm of jugular venous distension. Electrocardiogram showed low QRS volt- age and T wave inversion on V 1 –V 4 leads, and troponin I was negative. CT angiogram showed negative for pulmonary embolism; however, it demonstrated pericardial thickening and moderate sized pericardial efusion which are new com- pared to the prior study (Figures 1(a) and 1(b)). Subsequent echocardiogram showed septal bouncing and respiratory septal shif, suggesting ventricular interdependence and con- strictive efusive physiology. Total 3 L of fuid was given for low blood pressure. Bedsides pericardiocentesis drained 130 mL of serosanguinous fuid and subxiphoid pericardial window was performed the next day. Biochemical study from pericardial fuid showed LDH 794 IU/L, protein 4.3 g/dL, amylase 29 IU/L, and glucose 99 mg/dL. Fluid cytology, Gram stain, and culture were negative for neoplasm or microorgan- ism, and adenosine deaminase PCR was also negative. WBC count was 19,600/L with 90% of lymphocyte consistent with marked acute infammation. Pathology from pericar- dial tissue demonstrated acute fbrinous pericarditis without any evidence of malignancy or microorganism (Figure 2). Additional examinations for autoimmune disease including Hindawi Publishing Corporation Case Reports in Oncological Medicine Volume 2015, Article ID 794842, 5 pages http://dx.doi.org/10.1155/2015/794842