62


EQUINE VETERINARY EDUCATION / AE / FEBRUARY 2018


a)


GE L5


* 10 * 20 b)


GE L5


* * 10 0


0


20


Fig 2: Ultrasonographic images of the caudoventral abdomen of Case 2. a) There are several distended and amotile small intestine loops with thickened walls (arrowheads) surrounding an echogenic rounded mass (arrows) corresponding to a lipoma. There is large amount of anechoic peritoneal fluid (asterisks). b) There is a distended and amotile small intestine loop with thickened wall (arrowhead) attached to a thin linear hyperechoic band, consistent with small intestine mesentery (arrows). There is also moderate anechoic peritoneal fluid (asterisks).


The histopathological study confirmed the diagnosis of lipoma.


Discussion


Transcutaneous abdominal ultrasound is a complementary diagnostic procedure that has become an important part of the acute abdomen diagnostic work-up. It allows a thorough noninvasive evaluation of most abdominal organs and gastrointestinal viscera; however, this technique is limited by the size of the equine abdomen, the depth provided by the ultrasound transducers and the intraluminal gas within the gastrointestinal tract in horses with and without colic. Ultrasonographic features of small intestine strangulating


obstruction consist ofmarkedly distended, amotile loops of small intestine with or without thickened walls and ventral sedimentation (Reef 1998; Busoni et al. 2011; Bain 2014).


© 2016 EVJ Ltd


Authors’ declaration of interests No conflicts of interest have been declared.


Ethical animal research


This is a case report: recourse to ethical bodies was not undertaken.


Authorship All authors were involved in the clinical management of one of the cases. G. Manso-Dıaz and M. Martın-Cuervo wrote and


Continued on page 84


However, this ultrasonographic pattern can be caused by obstructive or partially obstructive lesions including intussusceptions, pedunculated lipomas, volvulus, epiploic foramen entrapment and inguinal hernias. In small animals, abdominal lipomas have been described to appear as avascular, well-defined hyperechoic masses within the abdomen (D’Anjou and Carmel 2015). Ultrasonographic characteristics of the lipomas described in this article are similar to what it is reported in small animals. In Case 1, a focal heterogeneous hypoechoic centre was identified within the mass, which corresponded histopathologically to a necrotic centre. This appearance has been described in the small animal literature in some abdominal lipomas (Mayhew and Brockman 2002). Ultrasonographic identification of intra-abdominal lipomas is complicated because they are often located deep within the abdomen and can be obscured by overlying gas-filled viscera. Transrectal ultrasonography was not performed in the cases presented in this article. However, it may be useful for further characterisation if lipomas were identified in the caudal abdomen on transcutaneous examination as it allows the evaluation of the most axial abdominal structures from the caudal abdomen and pelvic cavity (Schmidt 1989; Edens et al. 1996; Freeman et al. 2001; Navas de Solis et al. 2015). Furthermore, identification of a lipoma during an abdominal ultrasonographic examination in a horse does not necessarily mean that it is the cause of the clinical signs. This is illustrated in Case 2, where several lipomas were found during surgical examination of the small intestine. The mass identified on ultrasound may have represented either the pedunculated lipoma wrapped around the small intestine or one of the small masses observed attached to the mesentery. However, the size of the mass correlated with the size of the strangulating lipoma, suggesting that it was most likely to be the mass visualised on transcutaneous ultrasound examination. In both horses, the presence of peritoneal fluid improved the identification of the mass. Tumour types are difficult to predict ultrasonographically and other differential diagnoses should also be considered such as other abdominal neoplasms (Hillyer 1994; Freeman 2003; Knottenbelt 2014). In most cases, a definitive diagnosis of this condition is often achieved in surgery or post-mortem examination due to the nonspecific clinical signs; however, it is a common cause of small intestine strangulating obstruction as reported in the literature (Garcıa-Seco et al. 2005). In conclusion, abdominal ultrasonography offers a useful


diagnostic approach to identify intra-abdominal lipomas before performing an exploratory celiotomy in horses with colic. Lipoma should be a differential diagnosis for masses identified ultrasonographically within the abdominal cavity in the horse.


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