Regression Of Primary Tumor In Lung Adenocarcinoma: A Rare Case With Persistent Nodal Metastasis.

Spontaneous regression (SR) of pulmonary adenocarcinoma is an exceedingly rare event, characterized by the unexplained disappearance or reduction of a tumor without adequate medical intervention. We report a case of a 60-year-old male with a history of heavy smoking and previous gastric adenocarcinoma. A surveillance CT scan identified a suspicious nodule in the right upper lung. PET/CT and biopsy confirmed adenocarcinoma. The patient underwent right upper lobectomy, and histology showed no residual cancer, consistent with SR. Lymph node metastasis was detected, leading to a staging of pTxN2R1M0. The patient is currently with no signs of recurrence. SR in pulmonary adenocarcinoma is extremely rare, and its mechanisms are not well understood. Ongoing research and careful follow-up are essential for better understanding and management.