Leukemoid Reaction After Second Surgery for Locally Recurrent Lung Adenocarcinoma: A Case Report

Background Leukemoid reaction (LR) is defined as white blood cell (WBC) count exceeding 50×10 ⁹ /L. LR may be a paraneoplastic manifestation of various malignant tumors, unrelated to infections or malignant haematological disorders. LR with locally recurrent lung adenocarcinoma has been a rare observation. We report a rare case of a 64-year-old male who developed LR after underwent second surgery for locally recurrent lung adenocarcinoma. Case Presentation A 64-year-old man who was admitted to the hospital with left chest pain and dyspnea that started one week ago. He was diagnosed with left upper lobe lung adenocarcinoma (T1bN0M0; Stage IB) and underwent uniportal video-assisted thoracoscopic wedge resection of the left upper lobe in February 2021. During the postoperative follow-up the recurrence of left lung upper lobe adenocarcinoma was found by re-examination of chest computed tomography (CT) In March 2025, and he was diagnosed with left upper lobe lung adenocarcinoma (T3N2aM0; Stage IIIA) and underwent ledt upper lobectomy in March 28, 2025. On April 20, 2025, he was readmitted to hospital with left chest pain and dyspnea. The complete blood count revealed leucocytosis. After admission the WBC counts successively increased to 57.07×10 ⁹ /L within one week, respectively. Bone marrow aspiration and biopsy confirmed LR and ruled out any myeloproliferative disorder. Despite undergoing active treatment, the patient ultimately died of respiratory failure on the 13th day after admission. Conclusion LR in patients with recurrent lung adenocarcinoma after second surgery is very rare and associated with poor prognosis. For lung adenocarcinoma patients who are ineffective in anti-infection treatment and have gradually increasing white blood cell counts, bone marrow aspiration and biopsy should be promptly performed to rule out primary hematological malignancies. Early identification of LR and proactive management of the primary tumor play a significant role in the treatment and prognosis of cancer.