Lymphangioleiomyomatosis (LAM) is a rare, cystic, progressive lung disease with many extrapulmonary manifestations, which may complicate allograft function after transplantation. We present a LAM patient with new dyspnea and declining spirometry without rejection, infection or recurrence one year after bilateral lung transplantation. Investigation revealed acute constrictive pericarditis, which has not been reported previously in a lung transplant patient with LAM. This represents a novel complication likely due to progression of extrapulmonary LAM and should be considered in LAM transplant patients with dyspnea.