A two-year-old castrated male Pomeranian dog was referred with the chief complaints of
coughing and subcutaneous emphysema. On physical examination, the crepitant areas were
palpable. When auscultated, the right chest was absent of respiratory sound, while the
sound of the opposite side was enhanced. Radiographs presented pneumothorax and
pneumomediastinum. On computed tomography, hypoattenuated bulla-like lesion at right
middle lung lobe and trapped air in mediastinum were shown. After patient stabilization,
surgery for excision of affected lobe was performed. During follow-up period, there were
no recurrence and complication on radiographic examination. Based on clinical and
pathological findings, the dog was diagnosed as congenital lobar emphysema.
Feline pituitary tumors are rare. An 8-year-old male Japanese domestic cat presented with
anorexia and emaciation. The cat died 17 days after admission from progressive
neurological symptoms. At necropsy, a pituitary tumor measuring 25 × 18 × 15 mm was found.
Microscopically, the tumor was divided into multiple lobules and had grown invasively into
the adjacent brain tissue and sphenoid bone. Tumor cells had pleomorphic nuclei with
prominent centrally located nucleoli and abundant amphophilic polygonal cytoplasm.
Immunohistochemically, the tumor cells stained with anti-adrenocorticotropic hormone
(ACTH), α-melanin-stimulating hormone (MSH) and β-endorphin antibodies. Ultrastructurally,
the cytoplasm of the tumor cells contained various sized secretory granules. Based on
these pathological findings, this tumor was diagnosed as pituitary carcinoma originated
from pars intermedia cells.
An 11-year-old mixed breed dog
was presented with signs of anorexia. Radiographic and ultrasound examinations revealed a
large mass in the heart, between the right atrium and the right ventricle. Upon gross
inspection, a multilobulated tumor arising from the right atrial wall and occupying the
right atrium was identified. Microscopical analysis demonstrated that this tumor consisted
of neoplastic cells with granular cytoplasm, which were separated into nests by fine
fibrovascular stroma and were negative for Grimelius’s method. Immunohistochemical
examinations revealed that the neoplastic cells expressed chromogranin A, synaptophysin
and neuron specific enolase. Electron microscopy revealed that the cytoplasm of the
neoplastic cells held secretory granules. Based on these pathological findings, the tumor
was diagnosed as a paraganglioma. This report is a rare case of primary paraganglioma
deriving from the right atrium and provides a detailed characterization of its
morphological features.
Rabies is a zoonotic disease caused by the rabies virus. While the salivary glands are
important as exit and propagation sites for the rabies virus, the mechanisms of rabies
excretion remain unclear. Here, we investigated the histopathology of the salivary glands
of rabid dogs and analyzed the mechanism of excretion into the oral cavity. Mandibular and
parotid glands of 22 rabid dogs and three control dogs were used. Mild to moderate
non-suppurative sialadenitis was observed in the mandibular glands of 19 of the 22 dogs,
characterized by loss of acinar epithelium and infiltration by lymphoplasmacytic cells.
Viral antigens were detected in the mucous acinar epithelium, ganglion neurons and
myoepithelium. Acinar epithelium and lymphocytes were positive for anti-caspase-3
antibodies and TUNEL staining. In contrast, no notable findings were observed in the
ductal epithelial cells and serous demilune. In the parotid gland, the acinar cells,
myoepithelium and ductal epithelium all tested negative. These findings confirmed the path
through which the rabies virus descends along the facial nerve after proliferation in the
brain to reach the ganglion neurons of the mandibular gland, subsequently traveling to the
acinar epithelium via the salivary gland myoepithelium. Furthermore, the observation that
nerve endings passing through the myoepithelium were absent from the ductal system
suggested that viral proliferation and cytotoxicity could not occur there, ensuring that
secretions containing the virus are efficiently excreted into the oral cavity.
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