Crohn’s disease unmasks pulmonary sarcoidosis on biologic screening: dual granulomatous pathology responsive to infliximab

A man in his 30s with longstanding ileal Crohn's disease was found to have pulmonary sarcoidosis during routine pre-biologic evaluation. Although he had no respiratory symptoms, lung function testing showed mildly reduced diffusion capacity. Radiological imaging demonstrated diffuse pulmonary nodules and mediastinal lymphadenopathy, and transbronchial biopsies confirmed non-necrotising granulomas consistent with sarcoidosis. In the setting of postoperative endoscopic Crohn's recurrence and pulmonary sarcoidosis with mildly reduced diffusion capacity, infliximab was selected to provide dual disease control. Crohn's disease improved endoscopically and histologically, while follow-up CT showed radiological improvement of the pulmonary sarcoidosis. This case highlights the diagnostic complexity of overlapping granulomatous diseases and the potential therapeutic advantage of tumour necrosis factor-alpha inhibition when treatment of both conditions is being considered.