Objective:

To report two cases of pulmonary alveolar adenoma and review existing literature on this rare neoplasm.

Approach:

• Case 1: A 55-year-old female with left breast carcinoma presented with a lung nodule initially thought to be a metastasis. Surgical resection confirmed it as an alveolar adenoma.
• Case 2: A 35-year-old female with a history of heart transplantation and chronic kidney disease had a lung nodule detected during a PET-CT scan. Wedge resection confirmed it as an alveolar adenoma.

Key Findings:

• Alveolar adenomas are extremely rare, accounting for less than 1% of pulmonary neoplasms.
• Both cases presented as incidental findings or mimicked metastasis.
• Histological and immunohistochemical profiles confirmed the diagnosis of alveolar adenoma in both cases.
• No significant genetic alterations were identified by next-generation sequencing.

Interpretation:

The rarity of alveolar adenomas necessitates their consideration in differential diagnoses for lung nodules, especially in patients with a history of malignancy.

Limitations:

• The true incidence of alveolar adenomas may be underestimated due to incidental detection.
• Comprehensive molecular profiling has not been widely performed in existing literature.

Conclusion:

Alveolar adenomas, while rare, should be recognized in clinical practice, particularly in patients with other neoplasms.