Defining the lymph node burden in a Northern European population without malignancy: the potential effect of geography in determining a need for FNA?

Data from the USA suggest that morphological specificity is insufficient to permit an assumption of malignancy in nodal staging with endoscopic ultrasound (EUS). This may not hold true elsewhere as the background lymph node burden may vary in different geographic regions. We aimed to assess the prevalence and features of mediastinal and abdominal lymph nodes at EUS in a Northern European population without malignant disease. A total of 129 consecutive patients without malignant disease referred for radial EUS were prospectively evaluated for the prevalence and echo features of lymph nodes in the mediastinum and upper abdomen. Sixty-two percent of patients had mediastinal lymph nodes and 17% had abdominal nodes at EUS. A mean of 1.4 (standard deviation 1.3, range 0-8) nodes were found per patient. No celiac nodes were seen. The majority of detected nodes were 0.5 cm or less in short axis, had oval shape, centrally echogenic pattern, and indistinct borders. The most common node locations were the subcarinal and paraesophageal areas, and the hepatoduodenal ligament. In multivariate analysis mediastinal lymphadenopathy was related to body mass index and abdominal lymphadenopathy to acute pancreatitis. The occurence of mediastinal lymphadenopathy is markedly lower in Northern Europeans than reported for US patients. Celiac nodes are extremely rare in patients without malignancy. The majority of nodes have a width of 0.5 cm or less, have oval shape, centrally echogenic pattern, and indistinct borders. The characterization of the background lymph node burden may improve the selection of lymph nodes for fine needle aspiration.