case_images: PMC5826211_01
case_images: Survey thoracic radiographs including left lateral (A) and ventrodorsal (B) views revealed diffuse dilation of the cervical and thoracic portions of the esophagus. There are no obvious abnormalities associated with the pulmonary parenchyma, cranial mediastinum or vasculature, or the cardiac silhouette. Diffuse megaesophagus was confirmed.
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case_images: PMC5826211_01_fvets-05-00020-g001.jpg
case_images: F1
case_images: Thoracic radiographs showed generalized megaesophagus with no abnormalities noted in the pleural space, cranial mediastinum, or pulmonary parenchyma (Figure 1).
case_images: Cryosections from the triceps muscle at low [H&E stain (A)] and higher [H&E stain (B)] power illustrate the marked variability in myofiber size with atrophic fibers having a distinct perifascicular distribution. Scattered necrotic fibers undergoing phagocytosis are also evident. Many perifascicular fibers show intense dark blue staining with the oxidative reaction NADH-TR (C). Small caliber blood vessels [(D) esterase reaction] with thickened walls (dark arrows) were present within the perimysium. A cluster of brown stained esterase reactive macrophages were adjacent to one of the vessels.
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case_images: PMC5826211_01_fvets-05-00020-g002.jpg
case_images: F2
case_images: A moderate variability in myofiber size was present in both muscles with atrophic fibers having a round shape and a marked perifascicular distribution (Figure 2).
case_images: Immunofluorescence staining of frozen sections from the triceps muscle using a monoclonal antibody against developmental myosin heavy chain (dMHC) highlights the perifascicular distribution of immature muscle fibers. Scattered cells were highlighted with the antibodies against CD3 and CD8 leukocyte antigens but no CD4 positive cells were noted. Numerous cells were highlighted with the CD11c antibody against macrophages and dendritic cells. Using the antibody against MHC I, muscle sarcolemmal and internal labeling of myofibers was evident in some but not all myofibers. Bar in MHC I image also = 50 microm for CD3, CD4, CD8, and CD11c images.
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case_images: PMC5826211_01_fvets-05-00020-g003.jpg
case_images: F3
case_images: Studies Hybridoma Bank, University of Iowa, Figure 3) The perifascicular pattern of muscle fiber atrophy was highlighted with the antibody against dMHC, confirming the immaturity of the atrophic fibers (Figure 3). Scattered CD3 and CD8 positive T cells were present.
case_images: H&E stained photomicrographs showing infiltration and partial replacement of the esophageal myenteric plexus (A), heart (B), and vagus ganglion (C) by a population of neutrophils, macrophages, lymphocytes, and eosinophils. Also notice the peripheralization of Nissl substance and central chromatolysis of some neurons in the vagus ganglion. (D) A chronic, wedge-shaped infarct is present within the renal cortex.
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case_images: PMC5826211_01_fvets-05-00020-g004.jpg
case_images: F4
case_images: Necropsy revealed myositis, endocarditis, myocarditis and epicarditis, and ganglioneuritis within the plexuses of the colon, esophagus, and vagus nerve (Figure 4).
case_images: H&E stained photomicrograph showing infiltration and partial replacement of the colonic myenteric plexus by a population of neutrophils, macrophages, lymphocytes, and eosinophils.
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case_images: PMC5826211_01_fvets-05-00020-g005.jpg
case_images: F5
case_images: The majority of ganglia examined [Meissner's/submucosal and Auerbach's/muscularis propria within the colon wall (Figure 5), myenteric plexuses within the esophagus, and the ganglia of the vagus nerve] were infiltrated by inflammatory cells (eosinophils, neutrophils, macrophages, and lymphocytes).