Rare case of association of mesenteric volvulus and left hepatic hypoplasia in a German Shepherd Dog

We report a rare case of association of mesenteric volvulus and left hepatic hypoplasia in an approximately 6-year-old, uncastrated male German Shepherd Dog. The small and large intestines were displaced from their normal anatomical position and intensely dilated, with diffusely hyperaemic and haemorrhagic serosae. The mesenteric root, at its insertion into the roof of the abdominal cavity, was twisted 360° counterclockwise along its axis. The small and large intestines had thick, haemorrhagic and oedematous walls, with liquefied, bloody and fetid contents throughout. The left medial and lateral hepatic lobes and the caudate process of the caudate lobe were markedly reduced in size, while the right medial lobe was slightly enlarged, indicating left hepatic hypoplasia with mild compensatory right-sided hypertrophy. Intestinal samples tested negative for Clostridioides difficile, Salmonella spp, canine parvovirus, Giardia spp and Campylobacter spp. Microscopic analysis revealed diffuse necrosis of the mucosa and marked diffuse haemorrhage in the intestines, with preservation of crypts. In the lamina propria, a mild lymphoplasmacytic infiltrate was present, along with some intact and degenerated neutrophils. The only histological difference observed between the hypoplastic and normal hepatic lobes was moderate biliary hyperplasia and hypertrophy. Based on the macroscopic findings, the diagnosis of mesenteric volvulus and left hepatic hypoplasia was confirmed, both of which are considered rare in dogs. The severity of the hepatic hypoplasia may have predisposed to mesenteric volvulus.