What happened, in summary

A 65-year-old man was evaluated after an accidental injury in August 2024, when chest imaging unexpectedly found a 3 cm mass in the right upper lung with involvement of hilar lymph nodes. He had a heavy smoking history but no abnormalities on head or abdominal imaging.

He underwent a right upper lobectomy with systematic mediastinal lymph-node dissection. Pathology showed poorly differentiated lung adenocarcinoma. The tumor had loss of SMARCA2 expression while SMARCA4 was preserved. Genomic testing did not identify a driver mutation, and PD-L1 expression was at least 1%.

One month after surgery, he began adjuvant carboplatin and pemetrexed and completed 4 cycles. Through April 2025, follow-up had found no signs of recurrence. His case was presented alongside another patient with the same rare molecular pattern to explore why SMARCA2-deficient lung adenocarcinoma may behave aggressively in some people despite preserved SMARCA4 expression.