Pulmonary Langerhans cell histiocytosis presenting as a solitary nodule

Area of Science:

• Pulmonology
• Oncology
• Pathology

Background:

• Pulmonary Langerhans cell histiocytosis (PLCH) is a rare lung disease.
• PLCH commonly presents with diffuse lung involvement, often interstitial disease.
• Solitary pulmonary nodules are an uncommon presentation of PLCH.

Observation:

• A case of a 45-year-old male smoker with an asymptomatic solitary pulmonary nodule is presented.
• The nodule exhibited histologic and immunophenotypic features of PLCH.
• The patient remained asymptomatic with no interstitial disease 21 years post-excision.

Findings:

• A new contralateral lung nodule developed 21 years after initial diagnosis.
• The new nodule remained stable over 36 months of observation.
• This case highlights PLCH as a cause of isolated pulmonary nodules.

Implications:

• Solitary pulmonary nodules in PLCH may not predict interstitial lung disease.
• PLCH should be considered in the differential diagnosis of solitary pulmonary nodules.
• This case expands the understanding of PLCH clinical presentations.