Imaging Diagnosis—radiographic, Ultrasonographic, and Computed Tomographic Characteristics of a Duodenal Duplication Cyst in a Young Cat

Abstract

A 7-month-old, 2.8 kg, intact female Siamese cat was evaluated for repetitive and intermittent episodes of vomiting and anorexia. Abdominal palpation revealed a round, firm, nonpainful mass in the right cranial abdomen. Ultrasonography findings were consistent with a cystic structure adjacent to the descending duodenum. The structure exhibited a "muscular rim sign." A duodenal duplication cyst was confirmed by histopathological analysis. Computed tomography ruled out concurrent vertebral anomalies and clarified anatomic relationships for surgical planning. To the authors' knowledge, this is the first description of an ultrasound "muscular rim sign" in a duodenal duplication cyst in a cat.

Feline abdominal ultrasonography: What’s normal? What’s abnormal? The diseased gastrointestinal tract

“…80 Cysts arising at the level of the oesophagus, 75 duodenum, 81 jejunum, 82 ileum, 82 colon 83 and rectum 77 have all been described in the cat. Similar to humans, 79 affected cats are usually presented at a young age, most <2 years old, 74,80–82 although the condition is occasionally recognised in older animals, presumably as a result of clinical signs being overlooked and/or enlargement of the cyst as secretions accumulate. 77 Indeed, a search of the human literature reveals occasional reports of patients with enteric duplications and medical histories of chronic constipation (up to 20 years’ duration) prior to a correct diagnosis being made.…”

“…In other cases, some cats may be asymptomatic 79,82 and the duplication cysts only identified by the presence of a palpable abdominal mass. 74,78–80,82…”

“…74,82 The cyst wall thus comprises an inner hyperechoic rim (the mucosa) surrounded by an outer hypoechoic layer (muscular layer), an appearance that is considered to be relatively specific for this condition. 74,79…”

Carcinoma arising from an oesophageal duplication cyst in an adult cat

“…On ultrasonography, the caudal mediastinal cystic‐like mass of this cat had a double‐layered wall or muscular rim sign (inner echogenic mucosal and outer hypoechoic muscular layers). A presumptive diagnosis of duplication cyst suspected on the basis of the muscular rim sign 5. Other ultrasonographic differential diagnosis include the same previously described on radiographs.…”

“…Alimentary tract duplication cysts are uncommon congenital abnormalities reported in human beings, dogs and cats and can occur anywhere along the gastrointestinal tract 1 2. In cats, duplication cysts have been reported in the duodenum,3–5 ileum,6 colon,7 rectum8 and oesophagus 4. A rare complication of these cysts is malignant transformation 9.…”