Cessation is key: A case of pulmonary langerhans' cell histiocytosis (PLCH)

Abstract

Langerhans' cell histiocytosis (LCH) is a rare condition that affects adults, primarily between ages 20 to 40. The majority presents with single organ pulmonary involvement, often with abnormal imaging studies that may be accompanied by cough and/or dyspnea. A sixty-six year-old female presented to her local physician for persistent cough with clear sputum, mild hoarseness and progressive dyspnea. She denied fevers or night sweats but complained of general malaise and forty pound weight loss over 3 months. She had smoked for thirty five years and had occasional bouts of bronchitis during previous winters. She was initially treated with antibiotics, but when symptoms persisted, a chest CT scan was performed which showed innumerable nodular lesions with predominance within the upper lung fields. A PET scan showed sufficient FDG uptake that surgical lung biopsy was performed. Rather than the expected carcinoma, pathology suggested Langerhans' cell histiocytosis. She quit smoking the day of her biopsy and no active treatment was offered. Her cough progressively improved and became mild and intermittent with clear sputum, although she continued to have dyspnea on exertion. Pulmonary function tests (PFTs) showed mild airflow obstruction and reduced diffusing capacity (50% predicted) but with little improvement over 6 months. A chest CT done 5 months after diagnosis showed significant resolution of the nodular lesions with modest centrilobular emphysema remaining. Due to continued dyspnea, she underwent cardiac evaluation with echocardiogram and coronary angiogram, which were unremarkable. An overnight oximetry led to a polysomnogram and initiation of CPAP with improvement in her daytime fatigue. Due to continued dyspnea, treatment with prednisone was initiated and when little improvement was achieved, she was referred to our facility for further evaluation. Upon presentation, she continued to have mild clear sputum production with occasional cough and dyspnea on exertion. She had been significantly inactive since diagnosis and had regained all of the previously lost weight. Physical exam was significant only for obesity (BMI 37.9). A repeat chest CT and PFTs revealed continued improvement with her diffusing capacity now at 73% as predicted. ECG, echocardiogram, overnight oximetry (on CPAP) and baseline laboratory studies were normal. Review of the outside pathology confirmed pulmonary Langerhans' cell histiocytosis with background bronchiolitis. The patient's dyspnea was felt to be secondary to deconditioning and obesity, and she was advised a rigorous weight loss and exercise program coupled with continued tobacco abstinence. The pathogenesis of LCH is unknown, but nearly all cases of pulmonary involvement occur in current or previous smokers. This case is unique in that it illustrates the presentation of an infrequent illness and the remarkable benefit of smoking cessation on disease regression. The bulk of her improvement occurred prior to corticosteroid therapy which likely contributed only side-effects rather than benefit.