Initial Misdiagnosis of Lung Cancer due to Elevated Carcinoembryonic Antigen in a Patient with Tuberculosis.

Background: Tuberculosis often presents on imaging in the form of a solitary nodule, sometimes accompanied by elevated CEA, which is clinically difficult to differentiate from lung cancer and prone to misdiagnosis.

Methods: Lung tissue taken by lung biopsy and sent for NGS and Xpert MTB/RIF finally led to the definitive diag-nosis of nodular foci in the upper lobe of the left lung caused by tuberculosis.

Results: Enhanced CT of the chest showed nodular foci in the upper lobe of the left lung. Initially the nodules were thought to be malignant, but after a series of tests, were finally confirmed to be tuberculosis.

Conclusions: In patients with lung disease, when chest imaging reveals a space-occupying lesion accompanied by an elevated CEA level, a comprehensive analysis of the type of lung disease, the patient's age, and comorbidities should be performed before final diagnosis to avoid misdiagnosis and delay in appropriate treatment.