INTRODUCTION: Pulmonary Langerhans cell histiocytosis (PLCH) is a rare cause of interstitial lung disease associated with cigarette smoking, typically in young adults. We report a case of an older patient demonstrating rapid radiographic worsening of PLCH, followed by very rapid radiographic improvement after smoking cessation.
CASE PRESENTATION: A 71 year old male with a history of obstructive sleep apnea, 100 pack year smoking history and emphysema presented for evaluation of pulmonary nodules, discovered several months previously. He had developed progressive dyspnea on exertion during the past 12 months and a cough 5 months prior. Chest X-ray was abnormal and CT revealed multiple bilateral 3-4 cm pulmonary nodules that were new compared to a CT scan from 2 years prior. The patient initially declined biopsy. A follow-up CT scan 4 months later demonstrated that the nodules had increased in size to greater than one cm and were located predominantly in the middle and upper lobes. A CT guided biopsy was non-diagnostic. Another CT scan 2 weeks later showed significant progression of the bilateral pulmonary nodules and a VATS wedge lung biopsy was performed. Initial pleural fluid cytology showed inflammatory cells with benign mesothelial cells while initial pathology from the wedge biopsy revealed interstitial pneumonia. No evidence of malignancy was identified from either specimen. Physical examination was only significant for a prolonged expiratory phase. Laboratory evaluation, including rheumatologic markers, was remarkable for an elevated rheumatoid factor. Pulmonary function tests exhibited mild obstruction with a moderate gas exchange abnormality. Further pathologic review of the wedge biopsy demonstrated peribronchiolar stellate-shaped nodular fibrotic scars with traction emphysema, respiratory bronchiolitis and scattered lymphoid aggregates. Both CD1a and S100 positive cells were identified in the specimen. A repeat CT scan obtained one month following intensive smoking cessation efforts revealed significant resolution of the majority of the pulmonary nodules but no significant change in pulmonary function testing. However, the patient did report improvement in his dyspnea.
DISCUSSION: PLHC is an interstitial lung disease associated with cigarette smoking and an incidence of approximately 1-2 per million. This process most commonly affects younger patients, having a peak age of 40 and is characterized by infiltration of tissues with large numbers of Langerhans cells, typically organized into granulomas1. Patients may present with constitutional symptoms, pulmonary symptoms, or may be asymptomatic with radiographic findings discovered incidentally. The diagnosis is usually made about 6 months after the onset of symptoms. Radiographically, the early stage of PLCH exhibits a diffuse nodular pattern, but with progression of disease, there is evolution into the cystic pattern2. Nodules are predominantly found in upper and mid lung zones while sparing the lower lobes. Definitive diagnosis typically requires a surgical lung biopsy, and immunostaining should be performed for the S-100 protein and CD1a to confirm the diagnosis. Smoking cessation is the cornerstone of treatment, although there are reported cases of spontaneous disease resolution1,3.
CONCLUSIONS: To our knowledge, this case represents the oldest reported patient with PLCH and further demonstrates the unusual finding of extremely rapid radiographic progression of pulmonary nodules, followed by prompt radiographic resolution and symptomatic improvement with smoking cessation. Continued follow-up of the nodules will be necessary in light of the extensive smoking history.
Reference #1 Tazi, A. 2006. Adult Pulmonary Langerhans’ Cell Histiocytosis. European Respiratory Journal 27(6), 1272.
Reference #2 Abbott, GF, Rosado-de-Christenson, ML, et al. May-June 2004. Pulmonary Langerhans Cell Histiocytosis. Radiographics 24(3), 821.
Reference #3 Mogulkoc, N, Veral, A, et al. 1999. Pulmonary Langerhans’ Cell Histiocytosis: Radiologic Resolution Following Smoking Cessation. Chest 115, 1452.
DISCLOSURE: The following authors have nothing to disclose: Daniel Casey, Robert Herscowitz, Robin Gross
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