Complex sentence: Pulmonary Langerhans cell histiocytosis (PLCH) is a smoking-related interstitial lung disease, used to be considered a benign condition in adults, long term complications like pulmonary hypertension is becoming increasingly recognized.
Split into simpler sentences: Pulmonary Langerhans cell histiocytosis (PLCH) is a smoking-related interstitial lung disease. It was once considered a benign condition in adults, but long term complications like pulmonary hypertension are becoming increasingly recognized.