Yukihito Yamada

A Study on Myogenic Tumors of the Upper Gastrointestinal Tract by Endoscopic Ultrasonography—With Special Reference to the Differential Diagnosis of Benign and Malignant Lesions

Seventy‐six myogenic tumors (60 leimyomas, 3 leiomyoblastomas, 13 leiomyosarcomas) surgically resected from the upper gastrointestinal tract were studied histopathologically to define the characteristics of benign and malignant tumors. Twenty‐nine of these lesions (22 leiomyomas, 3 leiomyoblastomas, 4 leiomyosarcomas) were additionally studied by EUS before resection to investigate the relationship between EUS and histopathological findings and establish a scoring system enabling the differentiation of malignant from benign lesions. The results indicated that coagulative necrosis and bleeding were principally responsible for the heterogeneous internal echo of tumors. Anechoic areas corresponded to colliquative necrosis or cystic degeneration. Five EUS findings of prime importance in identifying malignant myogenic tumors were found to be: (1) a tumor diameter of ±3.0 cm, (2) nodular shape, (3) an ulceration depth of ± 5 mm, (4) a heterogeneous internal echo, and (5) the presence of an anechoic area. Each of these five parameters was assigned a score of 1 Point, and lesions with a total score of 3 or more were evaluated as being malignant. The sensitivity and specificity of our scoring system for myogenic tumors were respectively 100% and 73% in the 29 cases studied by EUS and 100% and 80% for all 76 tumors studied histopathologically.

CLINICAL USEFULNESS OF NEWLY DEVELOPED ELECTRONIC 360° RADIAL ENDOSCOPIC ULTRASONOGRAPHY

After the development of the mechanical radial scanning echoendoscope by Olympus Medical Systems (Tokyo, Japan), endoscopic ultrasonography (EUS) has become an indispensable examination in the clinical fields. Although mechanical radial EUS has no Doppler function because of its scanning method, Olympus Medical Systems developed a new electronic 360° radial EUS in 2003. Newly developed electronic radial EUS provides better penetration, fewer artifacts, color Doppler and power Doppler function, and tissue harmonic imaging. Its maneuverability is nearly the same as conventional mechanical radial EUS. With Doppler function it is easy to differentiate solid tumors such as pancreatic cancer, islet tumor etc., and to diagnose vascular invasion. Although there are some problems, electronic radial EUS has a promising future and it is believed that electronic radial EUS will become the standard model for the next generation of EUS equipment in imaging diagnosis.