SMARCA4-deficient lung cancer: no evidence of disease after lobectomy

What happened, in summary

A 63-year-old woman with a smoking history, hypertension, hypercholesterolemia, and previous surgeries for ductal breast carcinoma and pancreatic adenocarcinoma was evaluated after a CT scan on February 23, 2024, showed a solid right lower-lobe pulmonary nodule with bilateral emphysema. PET imaging was positive. A follow-up CT on May 8 showed progression of the nodule with new central cavitation. She was admitted on June 14, 2024, in good general condition without respiratory distress, and a multidisciplinary team recommended surgical treatment for a suspected neoplasm. She underwent right lower-lobe lobectomy through a standard posterolateral thoracotomy. Intraoperatively, the team found a solid tumor with surrounding inflammation and removed the tumor with a margin of healthy tissue, followed by careful hemostasis, chest-tube placement, and closure. Recovery was uneventful, with gradual improvement in respiratory function. Pathology of the 5.5 cm mass showed large round or rhabdoid discohesive cells, extensive geographic necrosis, and an immunoprofile with rare TTF-1-positive nuclei, Napsin-negative and p40-negative staining, CK7 positivity, focal Hepar-1 positivity, and negative alpha-fetoprotein, Glypican-3, estrogen receptor, and progesterone receptor staining. BRG-1 nuclear expression was predominantly absent, supporting SMARCA4-deficient non-small cell lung carcinoma under WHO 2021 criteria. A germline SMARCA4 mutation was considered because of her history of multiple cancers, but no clinical evidence or family history suggested an inherited syndrome. Follow-up included regular contrast-enhanced chest and abdomen CT plus symptom and pulmonary-function monitoring. No significant adverse effects were reported during hospitalization, and postoperative respiratory recovery was good. She was alive without evidence of disease, and all follow-up imaging was negative for recurrence.