INTRODUCTION: Pulmonary Langerhans cell histiocytosis [LCH] is a smoking-related interstitial lung disease characterized by development of bronchiolocentric lesions containing histiocytic cells called Langerhans cells. Treatment options for patients with pulmonary LCH are limited. We report a unique case of Langerhans cell histiocytosis with prominent lung, bony and lymph node involvement that responded to treatment with systemic 2-chlorodeoxyadenosine [2-CDA] treatment.
CASE PRESENTATION: The patient, a 66-year-old never smoker, initially presented at another facility with 1-2 months of shoulder pain and a left supraclavicular mass. Empiric antibiotic treatment for presumed infection did not improve symptoms or resolve the supraclavicular mass. Subsequently, a CT of the chest, abdomen and pelvis was performed and demonstrated cervical lymphadenopathy, several pulmonary nodules [the largest measuring 7 cm in the right lower lobe], and a 2 cm subcarinal lymph node. A deep cervical lymph node biopsy showed diffuse infiltration by S100 and CD1A positive Langerhans cells with areas of necrosis. Due to the presence of bilateral pulmonary nodules and subcarinal adenopathy, a bronchoscopy with BAL and biopsies was performed. Bronchoscopic biopsy of one of the nodular lesions demonstrated Langerhans cell histiocytosis. An MRI was obtained because there was a history of back pain. This demonstrated lesions involving multiple vertebral bodies. Due to multiple organ involvement from LCH with lung, bone, and lymph node disease, the patient was treated with 4 cycles of 2-CDA (5mg/m2). Following treatment, the patient reported resolution of back pain, and CT chest demonstrated near complete resolution of the lung lesions.
DISCUSSIONS: : Langerhans cell histiocytosis is characterized by proliferation and infiltration of organs by specific types of dendritic cells called Langerhans cells. Pulmonary LCH occurs predominantly in young adult smokers. Recent studies show that more than 90% of patients with pulmonary LCH are either current or former smokers. Patients may be asymptomatic at presentation. Radiologic findings vary depending on the stage of disease when imaging is obtained. Early in disease the predominant HRCT finding is the presence of small nodules, some of which demonstrate cavitation. In later stages of disease, cystic changes may be found and as the disease progresses to an advanced stage, the cystic changes predominate. The chest CT in pulmonary LCH rarely demonstrates pulmonary nodules without associated cavitation or cystic change, as observed in our patient. Treatment of LCH is primarily targeted toward smoking cessation, which frequently leads to stabilization. Although the overwhelming majority of patients with pulmonary LCH are cigarette smokers, it is important to recall that smoking is not an absolute requirement for development of disease. Indeed, most published series imply that approximately 5-10% of patients have no prior history of either personal or second-hand cigarette smoke exposure, as is the case in our patient. The decision to treat this patient was based on the presence of bony disease in the spine, rather than the lung involvement. Since the patient was a non-smoker, and had multiple organ involvement, we treated with systemic therapy. Corticosteroids have been used in the management, but there is limited data to support their efficacy. The antimetabolite 2-CDA was chosen because reports in the literature demonstrate its ability to induce complete or partial remission of disease in adult patients with refractory LCH.
CONCLUSION: This case is unique because it demonstrates a unique radiologic presentation of pulmonary LCH and documents near complete resolution of pulmonary lesions with 2-CDA therapy. The patient tolerated treatment with 2-CDA well without side effects. Treatment with 2-CDA should be considered as a therapeutic option in patients with progressive pulmonary LCH. Whether this agent has therapeutic activity in smokers with progressive pulmonary LCH remains to be demonstrated by prospective studies.
DISCLOSURE: Michelle Aerni, None.