Background: Nocardia infections can complicate solid organ transplantation. The usual clinical presentations include pulmonary infiltrates with or without cavitation and subcutaneous and brain abscesses. We report an unusual case of nocardia infection in a kidney transplant recipient that presented as mediastinal mass and was associated with pericardial tamponade.
Case Report: A 30 year old African American renal transplant recipient presented with cough, hoarseness and shortness of breath nine months after kidney transplantation. She received basiliximab perioperatively and her maintenance immunosuppression included tacrolimus, mycophenolate mofetil and prednisone. Computed tomography (CT) showed a large mediastinal mass with a large pericardial effusion. An echocardiogram revealed collapse of the right ventricle consistent with tamponade. We performed emergent pericardiocentesis to treat the tamponade. A mediastinoscopic biopsy of the mediastinal mass was done to establish a diagnosis. The mediastinal biopsy confirmed the growth of Nocardia. After 2 weeks of imipenem and 6 weeks of linezolid, there was marked radiographic improvement in the size of the mediastinal mass.
Conclusions: We report a rare case of a large mediastinal mass associated with pericardial tamponade from nocardia infection in a renal transplant recipient. An invasive approach may be necessary to obtain tissue diagnosis to direct treatment in these cases. Prompt and appropriate medical therapy leads to marked radiographic improvement.

Keywords: pericardial tamponade, mediastinal mass, Nocardia, Kidney Transplantation