We herein report an extremely rare case of pulmonary Langerhans cell histiocytosis with a solitary enlarged inguinal lymph node. A 19-year-old man presented with a non-productive cough lasting for over a five-month period and an enlarged left inguinal lymph node that had persisted for four months. A histopathological study of the lymph node specimens found Langerhans cells coupled with eosinophils. Positive immunohistochemical staining for langerin, Cluster of Differentiation 1a, S100 in the Langerhans cells confirmed the diagnosis, and a mildly impaired ventilation function in addition to multiple peripheral pulmonary cystic lesions were detected. The patient was managed with prednisone (0.5 mg/kg daily), with slow tapering over several months.