Hyperadrenocorticism Caused by a Pituitary Ganglioglioma in a Dog.

An 11-year-old castrated male Chihuahua dog was presented with complaints of polyuria, polydipsia, abdominal enlargement, and alopecia. Hyperadrenocorticism was diagnosed on the basis of clinical signs, blood tests, adrenocorticotropin-stimulation test results, and an elevated serum adrenocorticotropin concentration. Contrast-enhanced magnetic resonance imaging showed that the pituitary gland was enlarged, compatible with a pituitary macroadenoma. Pituitary-dependent hyperadrenocorticism was suspected, and transsphenoidal hypophysectomy was thus performed for complete resection of the tumor. After surgery, the serum adrenocorticotropin concentration normalized and the hyperadrenocorticism resolved. Histological and immunocytochemical analyses revealed a benign tumor composed of mature neuronal cells and glial cells, suggestive of a ganglioglioma with immunolabeling for adrenocorticotropin. Careful analysis of the resected tumor revealed no pituitary adenoma tissue. The clinical and histopathologic findings indicated that the ganglioglioma was directly responsible for the hyperadrenocorticism. This is the first case of hyperadrenocorticism caused by a ganglioglioma in a dog.

Desmoplastic ganglioglioma of the spinal cord in a western European hedgehog (Erinaceus europaeus).

Gangliogliomas are composed of neoplastic glial and neuronal cells and are extremely rare tumors of the central nervous system of domestic animals. The present report describes the clinical presentation and the pathomorphological and immunophenotypical characteristics of a desmoplastic ganglioglioma in the spinal cord of a 3-year-old male western European hedgehog (Erinaceus europaeus). Clinically, the hedgehog exhibited a skin wound and therapy-resistant paresis of the left hind limb. Necropsy showed dilatation of the urinary bladder. Histologic examination of the thoracic spinal cord revealed a focally extensive infiltrative mass, which consisted of multiple nodules of smaller bipolar or oligopolar glial cells and variably sized polygonal, ganglionic, neuron-like cells embedded in variable amounts of microcystic neuropilic matrix. An area of spindle-shaped cells arranged in interwoven fascicles and surrounded by a prominent network of reticulin fibers was interpreted as desmoplastic leptomeningeal stroma. Immunohistochemistry revealed a moderate number of glial fibrillary acidic protein and S-100-positive cells and processes. In addition, the ganglionic neuron-like cells expressed neurofilament, microtubule-associated protein-2, and neuron-specific enolase. In summary, this spinal cord tumor was composed of astroglial and neuronal cellular elements, justifying the diagnosis of a desmoplastic ganglioglioma.

Ganglioglioma in the thalamus of a puppy.

A solitary brain mass of a 4-month-old miniature dachshund showing seizure-like neurological signs was examined histopathologically. At necropsy a white tumor mass, replacing the thalamus, approximately 1.5 cm in diameter, was found. There was cystic space filled with yellowish pale fluid in the central area of the tumor mass. Histopathological examination revealed that the mass consisted of irregularly arranged well-differentiated neuronal and glial cells, and multifocal mineral deposits. The neuronal cells had a large clear nucleus and various amount of Nissl substances in the cytoplasm. Some neural cells were bi-nucleated. Neither mitotic figures nor proliferating cell nuclear antigen (PCNA)-positive nuclei was found in the neuronal cells. Immunostaining for glial fibrillary acidic protein (GFAP) revealed diffuse proliferation of GFAP-positive glial cells and their processes, while these glial cells did not show apparent cellular atypism, mitotic activity, or PCNA-immunoreactivity. Accordingly, the present tumor was diagnosed as ganglioglioma, and hamartomatous histogenesis might be possible.

An immunohistochemical study of peripheral neuroblastoma, ganglioneuroblastoma, anaplastic ganglioglioma, schwannoma and neurofibroma in cattle.

Immunohistochemical analysis of five paraffin wax-embedded neoplasms was performed to elucidate the characteristics of bovine nervous-tissue tumours. In case 1 (peripheral neuroblastoma), the neoplastic tissue was characterized by the formation of true and Homer-Wright rosettes and the existence of neuron-specific enolase. The neoplastic cells were possibly more immature than those of common neuroblastomas, because similar features are observed in human malignant neuroepitheliomas. The neoplastic cells in case 2 (ganglioneuroblastoma) ranged from large cells with abundant neurofilaments to immature small cells, rarely with neurofilaments or glial fibrillary acidic protein (GFAP). Such expression suggests the presence of pluripotential cells. The neoplastic tissue in case 3 (anaplastic ganglioglioma) was strikingly polymorphous, and had five elements; neuronal, astrocytic, oligodendrocytic, spindle cell and small oval cell. The neoplastic neurocytes and astrocytes were, respectively, characterized by neurofilament and GFAP positivity. The neoplastic oligodendrocytes made a honeycomb appearance, and the neoplastic spindle cells and small oval cells were considered to be less differentiated. The tumours of cases 2 and 3, which contained poorly differentiated cells and revealed both neuronal and glial differentiation, may be specific to calves. In case 4 (schwannoma), almost all the neoplastic cells were positive for S100 protein, while S100-negative fibroblasts were present in many areas of case 5 (neurofibroma). These two tumours were readily distinguished histologically and immunohistochemically.