Features of a rare peripheral primitive neuroectodermal tumour arising from the thoracic spine in a juvenile canine patient.

Peripheral primitive neuroectodermal tumours are rare tumours in juveniles. The current patient was a paraplegic 8-month-old Scottish deerhound with a suspected pulmonary mass. Radiographically, there was a large extrapleural mass within the mid-left hemithorax. On MRI, the mass was mainly hyperintense on T2-weighted images, isointense on T1-weighted images and was heterogeneously strongly contrast enhancing with a multilobulated appearance, spinal cord compression, paraspinal musculature invasion and intrathoracic extension. Those changes were confirmed on post-mortem, and the mass diagnosed based on immunohistochemistry.

Peripheral primitive neuroectodermal tumour in a dog.

A 1-year-old German shepherd dog was presented with paraparesis quickly progressing to paraplegia. Magnetic resonance imaging revealed a large mass beneath the thoracolumbar vertebral column infiltrating the spinal canal and resulting in severe extradural compression of the spinal cord. Microscopically, this comprised a cell-rich unencapsulated tumour supported by fine bands of a fibrovascular stroma and occasionally forming primitive rosettes. Immunohistochemistry showed the tumour cells to express synaptophysin and neuron-specific enolase. Ultrastructurally, the neoplastic cells had low to moderate numbers of intracytoplasmic neurosecretory granules. A peripheral primitive neuroectodermal tumour was diagnosed. This is a rare embryonal tumour of neural origin that may have arisen from adrenal medulla, autonomic ganglia or peripheral nerves.

Peripheral primitive neuroectodermal tumor in a two-year-old paint horse.

A 2-year-old gelding presented with a history of lethargy and anorexia. Physical examination revealed pleural and abdominal fluid, as well as several masses in the scrotum. The horse became acutely dyspneic despite 7 days of supportive care. Because of the poor prognosis, the owners elected euthanasia. Gross necropsy findings included multiple masses in the scrotum and inguinal canals and along the dorsal peritoneal cavity. The neoplasm infiltrated the kidneys, liver, spleen, mesenteric lymph nodes, mesentery, and abdominal surface of the diaphragm. Histologically, the neoplasm is composed of spindle to round cells arranged in densely cellular areas, vague streams, and rare rosettes. Neoplastic cells were immunoreactive for S-100 protein, glial fibrillary acidic protein, neuron-specific enolase, neurofilament protein, and synaptophysin. Based on gross, histological, and immunohistochemical findings, a diagnosis of peripheral primitive neuroectodermal tumor was made. Primitive neuroectodermal tumors are rarely described in horses that were associated with the eyes.

Cytologic and immunohistochemical characterization of a primitive neuroectodermal tumor in the brain of a dog.

A 6-year-old intact female Pointer dog was presented for evaluation of acute onset of ataxia, circling, and head tilt. Neurologic assessment revealed overall decreased postural reaction, left-sided hemiparesis with incoordination, rigidity of fore- and hindlimbs, strabismus of the right eye, and bilateral horizontal nystagmus. Using magnetic resonance imaging, a mass lesion was identified in the cerebrum adjacent to the left side of the cerebellum compressing the brain stem ventrally. The mass was incompletely resected, and during surgery fine-needle aspiration and biopsy of the mass were performed. Cytologically, smears were highly cellular and contained predominantly small to medium-sized discrete round cells with high nuclear to cytoplasmic ratios and round nuclei with rare deep clefts or indentation, smooth chromatin, and indistinct nucleoli. Numerous cytoplasmic fragments were noted in the background. The primary diagnosis was lymphoma; other differential diagnoses included neuroendocrine tumor and poorly differentiated tumor of neural origin. The histologic diagnosis was lymphoma, and the lesion was presumed to be metastatic. On immunohistochemical analysis, the cells expressed neither CD3 nor CD79a. Re-examination of the histologic section revealed disorganized sheets of cells with multifocal palisading and perivascular arrangements of rosette-like structures. An expanded panel of antibodies to vimentin, cytokeratin, glial fibrillary acid protein (GFAP), neuron-specific enolase (NSE), synaptophysin (SYN), S-100, and CD45 was applied to histologic sections. Neoplastic cells were immunoreactive for vimentin, NSE, and S-100. Based on the histologic appearance and immunophenotype of the tumor, a diagnosis of primitive neuroectodermal tumor (PNET) was made. PNET, although rare in dogs, should be considered as a differential diagnosis for round cell tumors in the brain.

A peripheral primitive neuroectodermal tumor with generalized bone metastases in a puppy.

A peripheral primitive neuroectodermal tumor (pPNET), most consistent with a human Ewing's sarcoma, is described in a 5-month-old male Australian Shepherd puppy. The first tumor site detected was in the left frontal bone of the skull with apparent subsequent rapid metastases to multiple sites in the axial and appendicular skeleton and bone marrow, kidneys, and perihyphophyseal meninges. Radiographically, all bone lesions were lytic and there was also a humeral bone fracture. Histologically, the tumor was diagnosed as a small round blue cell tumor. At this stage, the differential diagnosis included a lymphoma, rhabdomyosarcoma, and a PNET of the peripheral nervous system. However, the cells had positive expression of triple neurofilament antigens as detected immunocytochemically. The cells were negative for a broad panel of canine-specific leucocyte cell marker antigens for desmin, smooth muscle actin, synaptophysin, and CD99. Ultrastructurally, the cells contained occasional dense core neurosecretory granules and intermediate filaments with intercellular desmosomal-like junctions and abundant glycogen clusters. Based on the age of the dog, the clinical history, the distribution of gross lesions, histologic characteristics of a small round blue cell tumor, and immunocytochemical and ultrastructural evidence of neuroectodermal differentiation, a diagnosis of a pPNET similar to a human Ewing's sarcoma was made.

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study.

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.

Peripheral neuroblastoma and primitive neuroectodermal tumor in Japanese black cattle.

Peripheral neuroblastoma was found in a 1-year-old, male, Japanese black cattle (Case 1) and primitive neuroectodermal tumor was noted in 7-year-old, female, Japanese black cattle (Case 2). In Case 1, neoplastic tissue was replaced the right cranial vault and nasopharynx. A large, soft mass approximately 18 cm in diameter was also observed in the right mandibulopharyngeal area. In Case 2, a neoplastic mass of about 15 cm in diameter was found in the mandibulopharyngeal area. Histopathologically, massive necrosis showing a pseudopalisade arrangement was frequently observed in Case 1. On the contrary, Homer & Wright rosette formations of tumor cells were prominent in Case 2. Immunohistochemically, the proliferating cells in Case 1 were positive for vimentin, S-100, and neurofilament (NF) and those in Case 2 showed intense immunoreactivity for NF and neuron specific enolase, but were negative for vimentin and S-100. The different degrees of differentiation of the neoplastic cells originating from the neuroectoderm, might be reflected in their different morphological and immunohistochemical features.

Type C retroviral expression in spontaneous feline olfactory neuroblastomas.

Three cases of spontaneous olfactory neuroblastoma (ONB) in domestic cats were morphologically and immunocytochemically characterized. Diagnostic light microscopic features included Flexner and Homer-Wright rosettes, while ultrastructurally the cells had neuritic processes, intracellular intermediate filaments, and intercellular junctions. Immunocytochemically, the tumors stained positively for neuron-specific enolase, cytokeratins, and S-100 protein antigens. In each case, a key finding was the identification of numerous mature type C retroviral particles within the tumors. In one case, budding of viral particles from the plasmalemma of tumor cells suggested the source of mature particles. This cat and one other were tested, and both were serologically positive for feline leukemia virus (FeLV). The virus in the tumors was identified as FeLV by polymerase chain reaction and immunocytochemistry. No other neoplasms were found in any of the cats, nor was there similar evidence of active viral infection in other non-tumor tissues, including the brain. Although the relationship between FeLV infection and ONB is uncertain, our findings indicate that FeLV should be investigated as an etiologic agent of ONB.

Spontaneous olfactory neuroepithelioma in a domestic medaka (Oryzias latipes).

Tumors of the central nervous system in fish are rare, and only six cases of spontaneous olfactory neuroepithelioma have been reported. This is the seventh case, found in a medaka, Oryzias latipes. The tumor was noted near the right olfactory orifice and finally measured 1.5 mm in diameter. Histologically the tumor consisted of undifferentiated neuroblasts forming a few true rosettes. Mitosis was frequently observed. Tumor cells stained diffusely for neuron-specific enolase and sporadically for neurofilament proteins by immunohistochemical procedures. Additionally a few large tumor cells were positively stained for S-100 protein. Electron microscopy revealed that the tumor cells had extended cytoplasm in which parallel neurotubules and a few neuroendocrine granules were noted. In the perinuclear region, bundles of intermediate filaments and neuroendocrine granules were seen. Single cilia and a pair of centrioles were occasionally found, but no ciliated cells were found in this tumor. Some large tumor cells contained electron-dense intracytoplasmic inclusions which showed a crystalloid structure by high-magnification electron microscopy; however, this type of crystalloid has never been reported in neuronal tumors.

Immunohistochemical demonstration of keratin in canine neuroepithelioma.

Morphological features and immunoreactivity for cytokeratin (CK), glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE) of three canine neuroepitheliomas and three canine ependymomas were investigated. Neuroepitheliomas were in three German shepherds as intradural-extramedullary solitary masses, with spinal cord displacement between T10 and L2. Histologically, they contained tubules and acini, lined by epithelial cells with focal squamous metaplasia, rosette-like structures, and polygonal to spindle-shaped cells between tubules. Acini were empty or filled with a homogeneous, eosinophilic periodic acid-Schiff (PAS)-positive material. Mitotic indices varied from low to moderate. Ependymomas occurred in the third (two cases) and fourth ventricle in adult boxers. Histologically, they were composed of cells with an ill-defined, scant amphophilic cytoplasm, with a central round euchromatic nucleus; cells formed pseudorosettes, with a central fibro-vascular stroma. Neuroepitheliomas stained for CK, but ependymomas did not. Both failed to stain for GFAP, NSE, or phosphotungstic acid hematoxylin (PTAH). Thus, antibodies to cytokeratin are useful to distinguish neuroepitheliomas from ependymomas.

Malignant teratoid medulloepithelioma in a horse.

Enlargement of the left eye, corneal opacification, and blindness were clinical signs of a teratoid medulloepithelioma in a 5-year-old Standardbred mare. Diagnosis was made on histologic examination of the enucleated eye. Medulloepitheliomas are congenital intraocular tumors arising from primitive ciliary body epithelium. Their development is rare in domestic animals.

Neuroepithelioma in a middle-aged dog.

Paresis progressing to paralysis was caused by a neuroepithelioma located at the level of the L1-L2 interspace in a 7 1/2-year-old Golden Retriever. This tumor has never been reported in a dog more than 3 years old. The possibility of a neuroepithelioma should be considered in the differential diagnosis of paresis/paralysis in older dogs.

[The diagnosis of primary olfactory mucosa neoplasms demonstrated by an esthesioneuroepthelioma in the dog]. / Zur Diagnose primärer Riechschleimhauttumoren, dargestellt an einem Asthesioneuroepitheliom beim Hund.

In context with the first light and electron microscopic description of a spontaneous esthesioneuroepithelioma in a dog (10 year old female Labrador) general morpho- and etiopathogenetic problems concerning olfactory neoplasias were discussed. Because of its specific location and growth pattern, especially the development of true rosettes and pseudo-rosettes, the tumor was evaluated light microscopically as an esthesioneurogeneic one. The final classification was based upon ultrastructural peculiarities, as occurrence of ciliar structures, characteristic intercellular junctions, and the - although rare - appearance of dense cored vesicles.

Spinal cord medulloepithelioma in a dog.

Medulloepithelioma, an embryonal neural tumor, was diagnosed in a 6-month-old Bullmastiff. Clinical signs of incomplete, upper motor neuron, transverse myelopathy involving the hindlimbs were observed on examination. Myelography was required to identify the cause of clinical abnormality. The tumor involved the L1 spinal cord segment.

Neuroepithelial tumor of the optic nerve in a horse.

A nine-year-old horse was presented with severe exophthalmos of the right eye and a large mass in the vitreal cavity. The affected globe was enucleated and two months following surgery the horse was euthanized because of spread of the tumor into the calvarium producing compression of the brain stem and neurologic signs. Examination of tumor tissue by light and electron microscopic examination showed a mixed neoplasm of primitive neuroepithelium.

Olfactory neuroblastoma in a heifer.

A nasal neuroblastoma (esthesioneuroblastoma) extending into the brain in a heifer produced mouth breathing and proptosis. The mass filled much of the left nasal cavity, palatine sinus and maxillary sinus, with turbinate atrophy and deviation of the septum. Caudally the neoplasm extended into the nasopharynx and olfactory bulb. It was a cellular neoplasm composed of small, undifferentiated piriform cells showing infrequent pseudorosettes and immature axonal processes. Mitosis was common is some areas.