Two lung adenocarcinomas in the same lobe: multiple primaries or intrapulmonary metastasis?

Area of Science:

• Pulmonology
• Oncology
• Radiology

Background:

• Managing multiple pulmonary nodules requires careful evaluation.
• Distinguishing between primary lung cancers and metastases is crucial for treatment planning.

Observation:

• A 52-year-old woman presented with bilateral lung nodules initially stable for 18 months.
• Recurrence was noted five years later with nodule growth in the left lung segments 6 and 10.
• Diagnosis of synchronous double primary lung cancers was made based on clinical history and imaging.

Findings:

• Surgical resection (left lower lobectomy) and lymph node dissection were performed.
• Pathology confirmed mixed subtype adenocarcinoma (papillary and bronchioloalveolar carcinoma) in both lesions.
• Both tumors shared an L858R mutation in the epidermal growth factor receptor (EGFR) gene.

Implications:

• Shared genetic mutations (EGFR L858R) provided limited utility in differentiating synchronous primary lung cancers.
• Detailed patient disease history is vital for accurate diagnosis and management of multiple lung cancers.
• This case underscores the importance of long-term surveillance for indeterminate pulmonary nodules.