Idiopathic muscular hypertrophy of the oesophagus in the horse: a retrospective study of 31 cases

Videofluoroscopy, CT angiography, and ultrasonography of congenital esophageal stenosis in a Labrador retriever

A 7-week-old Labrador retriever presented for further investigation into acute onset regurgitation, following weaning from liquid to solid food. A videofluoroscopic swallow study demonstrated a severe, focal esophageal dilation in the mid-cervical region, with marked luminal narrowing distally. Computed tomography with angiography revealed esophageal stenosis, extending from C4-T2, secondary to circumferential esophageal wall thickening. With the concern for development of secondary aspiration pneumonia, the owners elected to euthanize the dog and consented to postmortem examination. A diagnosis of segmental, cervical esophageal muscular hypertrophy was made on necropsy, consistent with the fibromuscular thickening type of congenital esophageal stenosis reported in humans.

Esophageal smooth muscle hypertrophy causing regurgitation in a rabbit

A five-year-old rabbit was evaluated for a 7 to 8 month history of regurgitation, weight loss, and hyporexia. Previously performed whole body radiographs, plasma biochemistry results and complete blood count revealed had no significant abnormalities. A computed tomography (CT) scan revealed a circumferential caudal esophageal thickening. The animal received supportive care until euthanasia was performed 6 weeks later. Caudal esophageal smooth muscle hypertrophy was diagnosed on necropsy. This case indicates that regurgitation can occur in rabbits and advanced imaging can investigate the underlying cause.

Esophageal Dysfunction in Friesian Horses: Morphological Features

Megaesophagus appears to be more common in Friesian horses than in other breeds. A prevalence of approximately 2% was observed among Friesian horses presented to the Wolvega Equine Clinic and the Utrecht University Equine Clinic. In this study, morphologic changes in the esophagi of Friesian horses with megaesophagus were compared with those of 6 control horses. Of 18 horses with clinically observed megaesophagus, only 12 animals had esophageal dilation at necropsy, usually involving the thoracic portion. Muscular hypertrophy of the distal esophagus was present in only one-third of the affected horses, indicating that this change is not the most relevant cause of megaesophagus in Friesians. Increased deposition of clumped and disorganized collagen was present in these clinically affected horses mainly in the non-dilated portion of the esophagus. At necropsy, a decrease in neural elements and elastin was present principally in horses with megaesophagus. Mild degeneration and necrosis of the tunica muscularis along the entire length of the esophagus were present in clinically affected horses and encountered only rarely in control animals. There were no significant differences among affected and control horses with respect to inflammation, mineralization, or the number of cells of Cajal. The increased occurrence of megaesophagus in the Friesian breed compared with other horse breeds, together with the presence of abnormal collagen in very young foals, supports the hypothesis that megaesophagus is hereditary in Friesians.

Megaesophagus in Friesian horses associated with muscular hypertrophy of the caudal esophagus

Friesian horses have a perceived high rate of congenital or hereditary diseases, including megaesophagus, that may lead to choke and death. A retrospective study was performed to determine the prevalence and pathologic characteristics of esophageal disease in 852 horses, including 17 Friesians, that had been necropsied over a 6-year period at the Diagnostic Center for Population and Animal Health. Forty-two horses had grossly described esophageal lesions (25 muscular hypertrophy, 7 hemorrhage, 6 megaesophagus, 4 erosion/ulceration, 3 obstruction, 2 tears, 2 secondary neoplasms, 2 lymphoid patches, 1 thin wall, 1 esophagitis). Some of these lesions occurred concurrently in the same horse. Ten of these horses died or were euthanatized because of severe esophageal disease (6 megaesophagus causing tears in 2 horses, 3 esophageal obstruction with food bolus, and 1 esophagitis). All 6 horses with megaesophagus were Friesians. No cause for megaesophagus was noted in the necropsy reports; however, 5 of these 6 Friesians had marked caudal esophageal muscular hypertrophy (wall thickness: 1.9 ± 0.3 cm). Microscopic review of the esophagus of these Friesians confirmed smooth muscle hypertrophy, with no obvious fibrosis, degeneration, or loss of myenteric plexi. Unlike the Friesians, the 4 non-Friesian horses with severe esophageal disease had esophageal obstruction with an intraluminal food bolus or severe esophagitis. None had caudal esophageal muscular hypertrophy. It is concluded that in comparison to other horse breeds, Friesians have a higher prevalence of severe esophageal disease, specifically megaesophagus, that is commonly associated with marked caudal muscular hypertrophy.