Abstract

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease characterized by the accumulation of histiocytes within the airspaces or parenchyma of the lung. It almost always occurs in smokers between the ages of 20 and 40. Bronchoscopic interventions, such as transbronchial biopsy (TBB) and bronchoalveolar lavage (BAL), should be performed before other more invasive procedures, but their diagnostic yield is lower. TBB is frequently non-diagnostic due to inadequate sampling. BAL cellular analysis may show alveolar macrophage predominance, and the detection of >5% of CD1a-positive cells in BAL fluid is highly suggestive and specific for the disease; however, this increase is not observed frequently. Surgical lung biopsy is the most definite modality for diagnosis. Smoking cessation must be recommended for all patients. The prognosis for most patients is relatively good, particularly if longitudinal lung function testing shows stability. Here, we presented a 48-year-old smoker with an unusual and unexpected radiological presentation.