Pulmonary Langerhans Cell Histiocytosis Without Extrapulmonary Involvement: A Case Report and a Brief Review of the Literature

Abstract

Pulmonary Langerhans Cell Histiocytosis (PLCH) is a rare lung disease characterized by the abnormal accumulation of Langerhans cells in lung tissue, mainly occurring in the second or third decades of life. The disease was named Histiocytosis X, but the name was changed to PLCH. The term "eosinophilic granuloma" historically referred to the characteristic histological appearance, which includes eosinophil-rich inflammatory infiltrates alongside Langerhans cells. However, the preferred nomenclature now emphasizes the role of Langerhans cells, hence the widespread use of the term PLCH. Whether the stressor driving the disease course is external or internal has not yet been conclusively shown. The disease is classified within the group of rare diseases, but histopathology reports have suggested that it is underdiagnosed because of the scarcity of publications on this subject. The disease is hardly ever diagnosed when present without significant pulmonary manifestations or extrapulmonary involvement. There is no proposed treatment algorithm, and some outcomes appear unsatisfactory because of loss to follow-up, recurrence, or adverse effects from treatment. The clinical presentation of PLCH can mimic other chronic obstructive lung diseases, such as chronic obstructive pulmonary disease or asthma, given that affected individuals present with cough, dyspnea, chest pain, and sometimes wheezing on auscultation. Misdiagnosis or diagnostic delay is not infrequent as there is no agreement on the optimal diagnostic approach for PLCH. We present the case of a 53-year-old man who complained of mixed respiratory symptoms and was eventually diagnosed with PLCH. We also briefly review the pertinent literature on this uncommon condition.