Pathology results of endoscopic ultrasound-guided tissue acquisition in retroperitoneal masses: a multicenter study.

Background: Malignant etiologies are found in 70-80% of symptomatic retroperitoneal masses. Histology is required for diagnosis and treatment. Information about endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-GTA) is scant for retroperitoneal masses. This study aimed to assess the pathology results of EUS-GTA for diagnosing retroperitoneal masses.

Methods: This retrospective, multicenter study involved patients from 5 care centers. All patients with retroperitoneal masses who underwent EUS evaluation were enrolled. We recorded demographic and clinical characteristics, location and size of the mass, type of needle (FNA/FNB), and complications related to the procedure.

Results: A total of 43 patients were included. The median age was 50.5 (range: 23-83) years, and 22 (51.2%) were female. The initial symptom was abdominal pain in 23 (52.3%) cases and weight loss in 11 (25%). Initial imaging was by computed tomography in 33 (75%) patients. Diagnosis with EUS-GTA was reached in 67.5% (29/43) cases. The most frequent histological diagnosis was carcinoma, in 25.5% (11/43). A malignant etiology was found in 31 (72%): 20 were primary tumors from the retroperitoneum, and 11 were metastases. In patients with metastasis, surgery was avoided and medical treatment was indicated. No adverse events were reported.

Conclusion: EUS and EUS-GTA can frequently provide accurate tissue diagnosis and significantly impact the subsequent management.