Clinical and Histopathologic Characteristics of Recurrent Sarcoidosis in Posttransplant Lungs: 25 Years of Experience.

Lung transplantation is the definitive therapy for end-stage pulmonary sarcoidosis. While recurrent sarcoidosis in allografts has been described in several case reports, the incidence and clinicopathologic characteristics remain unclear. In this study, we characterize the clinical and histopathologic features of recurrent sarcoidosis diagnosed in posttransplant lung surveillance transbronchial biopsies (TBBx). We identified 35 patients who underwent lung transplant for pulmonary sarcoidosis during the study period. Among them, 18 patients (51%) experienced recurrent sarcoidosis posttransplant. These included 7 females and 11 males with mean age at recurrence of 51.6 years. The average time interval from transplant to recurrence was 252 days (22 to 984 d). All TBBx contained >4 pieces of alveolated lung tissue with no evidence of International Society for Heart and Lung Transplantation (ISHLT) grade A2, A3, or A4 acute cellular rejection; chronic rejection; or antibody-mediated rejection. There were 33 surveillance TBBx that contained granulomatous inflammation with a mean of 3.6 well-formed granulomas per TBBx (range: 1 to >20). Multinucleated giant cells were identified in 11 TBBx (33.3%), with 1 case containing asteroid bodies. While most of the granulomas were "naked granulomas," 5 cases (15.2%) showed prominent lymphoid cuffing. Two cases showed evidence of fibrosis. One of the granulomas had focal necrosis; however, no infectious organisms were identified by special stains and clinical correlation suggested this case represented recurrent sarcoidosis. Biopsies of recurrent sarcoidosis usually show multiple well-formed granulomas with giant cells in more than half of the cases, while lymphoid cuffing, fibrosis, asteroid bodies, and necrotizing granulomas are uncommon findings. Pathologists should be aware of these features, as recurrence of sarcoidosis following lung transplant occurs in more than half of patients.