Pancreas transplantation is an effective treatment option for patients with complicated diabetes mellitus. Pancreas allograft recipients are followed with laboratory markers such as serum amylase, lipase and glucose levels. Hyperglycemia may indicate severe acute rejection and has recently been associated with antibody-mediated (humoral) rejection. In this report, we describe a unique case of a pancreas-after-kidney (PAK) transplant recipient with the rare presentation of pancreatic panniculitis, biopsy-proven severe acute cellular and antibody-mediated pancreas allograft rejection and surprisingly well-preserved endocrine function despite treatment with high dose steroids. We discuss the clinicopathologic features of antibody-mediated pancreas rejection, including the importance of correlating pancreas allograft biopsy, C4d staining and donor specific antibodies, to diagnose antibody-mediated rejection and initiate the correct treatment.