Secondary pulmonary hypertension due to pulmonary Langerhans cell histiocytosis accompanied with panhypopituitarism.

A 65-year-old man presented to our hospital with complaint of acute dyspnoea. He smoked 30 cigarettes per day from age 20 to 52 years. Immunocytochemical findings revealed 6.3% of positive CD1a cells in the cell fraction of bronchoalveolar lavage, thus suggesting a diagnosis of pulmonary Langerhans cell histiocytosis (PLCH), after nine years since the first suspicion of PLCH. Furthermore, he was diagnosed with secondary pulmonary hypertension (PH) caused by progressed PLCH by right heart catheterization. At 59 years of age, he was diagnosed with panhypopituitarism, and persistent hormone replacement therapy was subsequently started by an endocrinologist. After the initiation of oxygen therapy and treatment with a combination of sildenafil and warfarin, an estimated pulmonary artery systolic pressure reduced 97.9 to 64.0 mmHg. We believed this is a rare case of PLCH with irreversible central nervous system (CNS) disorder in whom severe PH developed due to a long-term burden of PLCH in a middle-aged male.