Endoscopic ultrasound-guided biopsy of left and right adrenal metastases enabling pathological diagnosis and genomic profiling after nondiagnostic conventional biopsies: two case reports.

Obtaining adequate tissue for histologic diagnoses and genomic testing can be challenging in metastatic lung cancer, particularly when conventional biopsy approaches are nondiagnostic. The study reports an effective salvage strategy using endoscopic ultrasound (EUS)-guided adrenal tissue acquisition in two cases. A 66-year-old woman (case 1) developed recurrent lung adenocarcinoma with progressive metastases to the left adrenal, liver, and lungs following multiple lines of systemic therapy. A percutaneous biopsy of a suspected liver metastasis proved nondiagnostic. Subsequently, transgastric EUS-guided biopsy was performed, which confirmed metastatic adenocarcinoma originating in the lung. Oncomine-based genomic testing detected a human epidermal growth factor receptor 2 exon 20 insertion. Trastuzumab deruxtecan was subsequently introduced, resulting in disease stabilization for 6 months. A 75-year-old man (case 2) developed bilateral pulmonary nodules and a right adrenal mass detected on positron emission tomography. Bronchoscopy failed to yield diagnostic tissue. Following careful review of cross-sectional anatomy, EUS-guided biopsy of the right adrenal gland was safely performed via the duodenal bulb, confirming metastatic squamous cell carcinoma and yielding adequate tissue for genomic testing. EUS-guided adrenal biopsy, including transduodenal sampling of the right adrenal gland, may provide tissue for histopathologic and precision oncology testing, facilitating definitive diagnoses.