• Histiocytosis, Langerhans cell
• Pulmonary arterial hypertension
• Pulmonary fibrosis
• Sarcoidosis
• Scleroderma, systemic

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare cystic lung disease usually affecting young adults. It is predicted that PLCH is a lung tumor precursor associated with dysfunction of the myeloid dendritic cells in the lung.

A 70-year-old male patient presented with chronic cough and sputum. He had symptoms for 5 years and described shortness of breath on exertion for the previous 3 years. He had a 60 packs/year smoking history. Computerized tomography of the thorax revealed an 11-mm nodule in the right lung lower lobe superior segment and a 7-mm nodule in the right lung lower lobe poster basal segment. Those two nodules were resected by means of right thoracoscopic surgery. Pathological evaluation revealed a squamous cell carcinoma and PLCH.

Coexistent squamous cell carcinoma and PLCH suggest possible association between PLCH and lung cancer.

• Pulmonary Langerhans cell histiocytosis
• Lung cancer
• Squamous cell carcinoma
• BRAF
• Mitogen-activated protein kinase
• Case report

Pulmonary Langerhans Cell Histiocytosis (PLCH) is a diffuse lung disease that primarily affects young adults, with cigarette smoking playing a significant role in developing the disease. Patients with PLCH present with characteristic CT chest findings of small irregular nodules and upper zone cysts. Previously, larger nodules greater than 10 mm and cavitation have only been reported a few times in the literature. We describe the case of a 69-year-old male who presented with dyspnea, non-productive cough and weight loss, who was found to have multiple cavitary nodules on CT imaging of the chest. Histopathologic sampling of the lung revealed Langerhans cells which stained positive for S100 and CD1a, consistent with a diagnosis of PLCH. The patient was counselled to quit smoking as the mainstay of treatment. In 3-month follow-up his symptoms had largely resolved, with evidence of decreased nodule size on repeat CT imaging.

• Diffuse lung disease
• Interstitial lung disease
• Smoking

• BRAF mutation
• Bone and soft tissue
• Histiocitosis de células de Langerhans
• Hueso y partes blandas
• Langerhans cell histiocytosis
• Mutación BRAF