Which of the following are true regarding pulmonary Langerhans’ cell histiocytosis in adults?
a) Isolated pulmonary involvement is usual
b) It is strongly associated with cigarette smoking
c) Thin-walled cysts and bronchocentric nodules are characteristic HRCT features
d( It has a predilection for the lower lobes
e) Mediastinal lymphadenopathy is frequently seen
