Bronchiolar Adenoma Transforming to Invasive Mucinous Adenocarcinoma: A Case Report

Area of Science:

• Pulmonary Pathology
• Oncology
• Molecular Diagnostics

Background:

• Bronchiolar adenoma (BA) is a lung neoplasm typically considered benign.
• Histological features include nodular proliferation of bilayered bronchiolar epithelium with basal cells.
• Driver gene mutations are frequently found in BA, indicating neoplastic origins.

Observation:

• This report details the first case of BA with a KRAS mutation.
• The adjacent invasive mucinous adenocarcinoma (IMA) shared the identical KRAS mutation.
• A disrupted basal cell layer was noted at the interface between BA and IMA.

Findings:

• The identical KRAS mutation in both BA and IMA suggests a common clonal origin.
• Loss of basal cell layer continuity points to malignant transformation.
• This provides evidence for the malignant potential of bronchiolar adenoma.

Implications:

• Bronchiolar adenoma may possess malignant potential, challenging its benign classification.
• Understanding BA-to-IMA transformation pathways is crucial for accurate diagnosis and treatment.
• This case highlights the importance of molecular analysis in evaluating lung neoplasms.