Bronchiolar adenoma with unusual presentation: Two case reports

Area of Science:

• Pulmonary Pathology
• Oncology
• Genetics

Background:

• Retrospective analysis of two unusual distal bronchiolar adenoma cases.
• Review of clinicopathological, immunohistochemical, and genetic profiles.
• Focus on diagnostic challenges and potential malignant transformation.

Observation:

• Case 1: Mild cells, focal bilayer structures, negative for common mutations.
• Case 2: Atypical cells, focal bilayer structures, identified HER2 gene mutation.
• Immunohistochemistry for P63 and CK5/6 revealed varying bilayer structures.

Findings:

• Distal bronchiolar adenoma presents with diverse morphology.
• HER2 gene mutation identified in one case, suggesting potential prognostic significance.
• Uncertainty exists regarding classification as benign, atypical, or precursor lesions.

Implications:

• Need for further studies to determine the nature of atypical bilayer structures.
• Clarification of diagnostic criteria for atypical bronchiolar adenoma.
• Investigating HER2 mutation as a prognostic marker in these lesions.