Ultrasonographic Findings in 42 Horses with Cecal Lymphadenopathy

Cecal lymphadenopathy is an uncommon but important ultrasonographic finding seen in some horses with neoplastic, infectious, or inflammatory diseases of the abdomen. Authors’ address: University of California, Davis, School of Veterinary Medicine, One Shields Avenue, Davis, CA 95616; e-mail: [email protected].

1. Introduction

Mesenteric lymphadenopathy is commonly found on postmortem examination in horses with infectious, inflammatory, or neoplastic disease but has been rarely reported as an ultrasound finding. Mesenteric lymph nodes are not often visualized by ultrasound because of their location deep within the abdomen. The cecal mesentery, however, is located adjacent to the body wall in the right flank region and can be readily visualized in most horses. The purpose of this study is to describe ultrasonographic findings associated with cecal lymphadenopathy with clinical diagnosis and outcome.

2. Materials and Methods

Records were reviewed for horses presenting for abdominal ultrasound from August 1999 to July 2007. Cases were included if multiple cecal lymph nodes were visible adjacent to the lateral cecal artery and vein.

3. Results

Forty-two horses (age 3 months to 26 years) with cecal lymphadenopathy were identified. Horses presented for weight loss, fever, anorexia, lethargy, colic, and diarrhea. Additional ultrasound abnormalities included thickened intestine (90%), abdominal masses (29%), and abdominal abscessation (9.5%). Etiologies were categorized as inflammatory (n = 16), neoplastic (n = 14), or infectious (n = 12) on the basis of available clinicopathologic data. Twenty-one horses (50%) were euthanized or died within 6 months of diagnosis, 13 were improved, and eight were lost to follow-up. 

4. Discussion

The cecal mesentery is readily imaged in the right flank and caudoventral abdomen and should be evaluated as part of a complete abdominal ultrasound examination. Cecal lymphadenopathy was often associated with additional important ultrasonographic abnormalities. Such information was helpful and often warranted further diagnostic procedures such as biopsy, aspiration, or surgery for definitive diagnosis.