Unusual Findings of Langerhans Cell Histocytosis in a Young Asymptomatic Patient: Case Report

Cyst is described on high-resolution computed tomography (HRCT) as focal round area of parenchymal hyperlucency with a well-defined interface with normal lung. A relatively small subset of lung diseases should be suspected when cystic pattern is seen on HRCT. In particular, the differential diagnosis of this pattern relies upon features such as: cranio-caudal distribution, cystic shape, and coexisting pulmonary or extra-pulmonary findings. Pulmonary Langerhans Cell Histocytosis (PLCH) is a smoke-related disease associated with cystic pattern. PLCH is characterized by infiltration of Langerhans cells in pulmonary interstitium with varying pathologic findings and depend on disease stage. The findings usually consist of a heterogeneous combination of lung nodules and cysts with upper lobes predominance. Notably, the HRCT pattern of PLCH is often striking and usually suggests confident diagnosis. Nevertheless, cases with atypical features can be seen. This case report describes the ambiguous imaging findings of a biopsy-proven PLCH.