Interventional endoscopic ultrasound

Coagulation necrosis in malignant mediastinal nodes on endoscopic ultrasound: a new endosonographic sign

AIMS

Endoscopic ultrasound (EUS) can be used to assess mediastinal lymph nodes, and EUS-guided transoesophageal fine needle aspiration (EUS-FNA) can provide a tissue diagnosis. Previous studies suggest that a uniformly hypoechoic echotexture is a feature of malignant nodes, and echogenic structures within nodes are due to the normal hilum. Ill-defined, non-shadowing echogenic areas within malignant lymph nodes have been termed coagulation necrosis (CN) on neck ultrasound. The purpose of this study is to determine whether CN can be detected on EUS and be used as a predictive sign for malignancy in mediastinal lymph nodes.

METHODS

A total of 36 individuals who underwent EUS-FNA of mediastinal lymph nodes were initially included. A radiologist experienced in neck ultrasound, and blinded to the final diagnosis, reviewed hard-copy films for CN. Comparison was made with the EUS-FNA result and the final diagnosis.

RESULTS

Four patients were excluded because their films were deemed inadequate for retrospective diagnosis. The remaining 32 patients were all included, and 11 showed CN. Of the 11 cases, 10 had malignant cytology on EUS-FNA; and in the remaining case follow-up indicated a false-negative EUS-FNA. Of the 21 subjects with no CN, the final diagnosis was malignant in 12 and non-malignant in 9 cases. No participant with a final benign diagnosis had CN.

CONCLUSION

Echogenic structures within mediastinal lymph nodes on EUS are not necessarily due to the normal hilum. Careful analysis of the intranodal echo pattern may reveal CN. CN can be used as a predictive sign of malignancy and EUS-FNA should be targeted towards these nodes.

Endoscopic ultrasound in the localisation of pancreatic islet cell tumours

The role of endoscopic ultrasound (EUS) in the evaluation of entero-pancreatic endocrine tumours has evolved in conjunction with advances in other imaging methods. The high spatial resolution of this technique allows the detection of very small lesions and their precise anatomical localisation. In patients with biochemically proven insulinoma, EUS can be effectively used as a first line investigation, with a sensitivity of 94%. Combined with thin section CT, the sensitivity rises to 100%. There is also high sensitivity in diagnosing intrapancreatic gastrinomas but lower for those arising in the duodenal wall which require detailed duodenal evaluation at surgery. EUS in conjunction with Somatostatin Receptor Scanning (SRS) has a combined sensitivity of 93% for gastrinomas. EUS is recommended for screening of asymptomatic patients with genetically proven MEN1. There is a limited role for EUS guided biopsy in pancreatic endocrine tumours.