UNUSUAL CASE OF PULMONARY LANGERHANS CELL HISTIOCYTOSIS PRESENTING AS GROUND-GLASS OPACITY IN THE LOWER LUNG

초록

INTRODUCTION: Nodules and cysts with upper lobe predominance on high-resolution computed tomography (HRCT) are highly suggestive of pulmonary Langerhans cell histiocytosis (PLCH). Reticular opacities are findings indicating more advanced disease. Herein, we describe a case of PLCH diagnosed by biopsy at the ground glass opacity (GGO) area in the lower lung. CASE PRESENTATION: A 56-year-old man presented to our hospital with a recent paroxysmal cough on July 29, 2022. The patient had a medical history of diabetes mellitus and a smoking history of 36 pack-years. He was a construction worker for 20 years. Chest CT revealed subpleural GGO and traction bronchiectasis mostly in both lower lungs. No nodules or cysts were present in the upper or middle lung area. Forced vital capacity was 3.70 L(74% of the normal predicted value) and diffusing capacity for carbon monoxide was 61%. Video-assisted thoracoscopic biopsies were performed at the superior and laterobasal segments of the right lower lobe on September. Biopsy specimens showed patchy nodular stellate-shaped fibrosis and mononuclear cell infiltration in the peribronchiolar interstitium. On immunostaining, the infiltrating mononuclear cells were positive for CD1a and S-100. The infiltration was more prominent in the periphery of the stellate nodule. All these findings were consistent with scarred PLCH. DISCUSSION: PLCH develops predominantly in young smokers. A confident clinical diagnosis can be made based on the characteristic clinical presentation and ill-defined nodules or bizarrely shaped cysts with upper lobe predominance on HRCT. Classic LCH is characterized by patchy nodular infiltrates of varying cellularity that have a distinct peribronchiolar distribution and are typically stellate shaped. The requisite diagnostic feature of LCH is the presence of clusters of Langerhans cells within the nodules, which stain positively for S-100 and CD1a.