Lymph Node Metastases

Detection of lymphadenopathy is difficult by sectional imaging. Normal-sized lymph nodes may harbor mi-crometastases (Fig. 5-33), and some enlarged nodes are due to benign reactive hyperplasia.

The original EUS criteria of distinguishing between benign reactive and metastatic lymph nodes on the basis of echo texture, size, and margination (Fig. 5-34) is now undergoing intense doubt.53-56

In the past, the diagnosis of lymph node abnormalities on CT scans has been based on size criteria, with the upper limits of normal in the upper abdomen reported as varying from 6 mm to 11 mm.57,58 However, accuracy is limited by the presence of micrometastases and reactive nodal hyperplasia. A recent report of improved detection using thin-sector contrast enhanced helical CT offers additional criteria to size alone in diagnosing metastatic lymph nodes, based on attenuation and configuration.59 The nodal pathways in gastrointestinal cancers are documented in Chapter 6.

Fig. 5—33. Micrometastases in lymph node.

Histologic section demonstrates that metastatic cells in a small zone of a lymph node (arrows) would be undetectable by sectional imaging. (Courtesy of Clive Bartram, M.D., St. Mark's Hospital, Northwick Park, England.)

Fig. 5—33. Micrometastases in lymph node.

Histologic section demonstrates that metastatic cells in a small zone of a lymph node (arrows) would be undetectable by sectional imaging. (Courtesy of Clive Bartram, M.D., St. Mark's Hospital, Northwick Park, England.)

Fig. 5-34. Metastatic lymph node shown by EUS.

Enlarged, spherical hypoechoic, sharply marginated node (N) in a case of esophageal carcinoma fulfills the original criteria. (Courtesy of Paul Fockens, M.D., Academic Medical Center, Amsterdam, The Netherlands.)

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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