Endosonographic predictors of malignancy in a left adrenal gland in lung cancer patients – a comparison of EUS-b, CT and PET-CT

Patients with resectable lung cancer require invasive evaluation of the enlarged left adrenal gland (LAG). Few studies showed the utility of endoscopic ultrasound using ultrasound bronchoscope (EUS‑B) in LAG assessment. Moreover, little is known on the combination of computed tomography (CT), positron emission tomography-computed tomography (PET‑CT), and EUS‑B for predicting left adrenal metastasis.In this retrospective cohort study performed from 2012 to 2019, patients with left adrenal enlargement were evaluated by CT, PET‑CT, and EUS‑B, followed by complete endoscopic mediastinal staging. The adrenal glands were sampled by EUS‑B-guided fine‑needle aspiration. Patients were followed for 6 months.During the staging of lung cancer in 2176 patients, 113 enlarged LAGs (5.19%) were biopsied. Malignancy was reported in 51 LAGs (45.13%). Endoscopic ultrasound upstaged 7 patients (6.2%) and downstaged 11 patients (9.37%) after false CT or PET‑CT findings. There were no biopsy‑related complications. Radiologic predictors of left adrenal metastases had the highest yield at the following cutoff points: Hounsfield units >23, standardized uptake value >4.2, and LAG size >25 mm. Hypoechogenic LAGs with loss of sea‑gull shape on EUS‑B were associated with a 28.67‑fold higher likelihood of metastases. The sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for all ultrasound predictors were 86.21%, 85.45%, 85.84%, 85.45%, and 86.21%, respectively. When combined with radiologic features, the respective values were 93.10%, 94.55%, 93.81%, 92.86%, and 94.74%.Hypoechogenicity and loss of sea‑gull shape on EUS‑B are the most reliable predictors of left adrenal metastasis. The combination of CT, PET‑CT, and EUS‑B improves the noninvasive diagnosis of left adrenal metastases in lung cancer patients.