A Case of Canine Primitive Neuroectodermal Tumor(PNET).

Abstract

ABSTRACT. A 2-year and 6 month-old, female, Golden Retriever showed circling behavior and seizure. By magnetic resonance imaging (MRI) examination, a mass was found on the surface of the left cerebral hemisphere, invading to the left temporal muscle. The skull bone between them was destroyed. The dog was euthanized and necropsied. Histologically, the mass contained a lot of undifferentiated anaplastic cells, forming Homer-Wright rosettes and pseudopalisading patterns. Thus, the case was diagnosed as primitive neuroectodermal tumor (PNET). KEY WORDS: brain neoplasm, canine, primitive neuroectodermal tumor (PNET).J. Vet. Med. Sci. 63(1): 103-105, 2001 Primitive neuroectodermal tumor (PNET) and medulloblastoma are the most undifferentiated neoplasms of the nervous system which contain neoplastic cells with a very primitive nature of both neuronal and glial cells. The concept of PNET was first proposed for the cerebral tumor of children that showed poorly differentiated morphology in the human medical field [5]. After that, PNET has been applied to all embryonal neuroectodermal tumors including neuroblastoma, ependymoblastoma, medulloblastoma and retinoblastoma [10]. At the present, PNET is applicable to the primitive tumors which arise in the extracerebellar nervous system and can not be morphologically distinguished from medulloblastoma in the cerebellum [9]. In animals, PNET has been reported in a monkey [7], a cattle [12] and dogs and cats [13].In this paper, we describe details of histopathological nature of the PNET observed in the cerebrum of a young dog. To our knowledge, this is the first report on the PNET observed in the dog, as an original paper with pictures.A 2-year and 6-month-old, female, Golden Retriever showed depression, circling behavior and walking disturbance. She was referred to a veterinary hospital, and abnormal behaviors and seizure were observed at that time. Though temporary recovery had been obtained by administration of corticosteroid, and she could walk again even with left circling, the sight-loss of the right eye was observed. Then she came to the Veterinary Medical Center of the University of Tokyo for further examination. By magnetic resonance imaging (MRI) examination, a mass was found on the surface of the left cerebral hemisphere, invading to the left temporal muscle (Fig. 1). The skull bone between brain and the muscle lesions was destroyed. The dog was euthanized because of the poor prognosis and necropsied soon after death.At necropsy, a grayish white-colored mass (4 × 2 × 2 cm) was found on the left temporal surface of the cerebrum, invading to the left temporal muscle (Fig. 2). The skull bone at the lesion was destroyed. The cut surface of the mass was grayish white, and several yellow-colored necrotic foci scattered in the mass. The border between the tumor mass and normal cerebral tissue was not clear (Fig. 3). No lesions were observed in other organs.All the collected organs were fixed in 10% neutral-buffered formalin. Paraffin sections (2-6 µm) were stained with hema...

Nasal peripheral primitive neuroectodermal tumor in a heifer: case report

“…The age of the heifer in this case, as well as in the cases described in other studies (UCHIDA et al, 1998;LUCAS et al, 2003;BERROCAL et al, 2005), suggests a predilection to occur in young cattle. The gross aspects of the pPNET in this case were similar to those observed in dogs (KATAYAMA et al, 2001) and other cases in cattle (UCHIDA et al, 1998;LUCAS et al, 2003), and were characterized by a relatively delimited, white-to-gray tumor, where the sectioned surface had multiple foci of necrosis and hemorrhage (UCHIDA et al, 1998;KATAYAMA et al, 2001). Histopathologic findings are similar to prior reports (UCHIDA et al, 1998;KOESTNER et al, 1999;BERROCAL et al, 2005), which have described a proliferation of round cells with numerous elongated cells in a carrot shape, arranged in nests or cords.…”

“…The gross aspects of the pPNET in this case were similar to those observed in dogs (KATAYAMA et al, 2001) and other cases in cattle (UCHIDA et al, 1998;LUCAS et al, 2003), and were characterized by a relatively delimited, white-to-gray tumor, where the sectioned surface had multiple foci of necrosis and hemorrhage (UCHIDA et al, 1998;KATAYAMA et al, 2001). Histopathologic findings are similar to prior reports (UCHIDA et al, 1998;KOESTNER et al, 1999;BERROCAL et al, 2005), which have described a proliferation of round cells with numerous elongated cells in a carrot shape, arranged in nests or cords. A palisade distribution pattern is common; occasionally, neoplastic cells were arranged in structures similar to Home-Wright and Flexner-Wintersteiner rosettes.…”

“…A palisade distribution pattern is common; occasionally, neoplastic cells were arranged in structures similar to Home-Wright and Flexner-Wintersteiner rosettes. Frequent mitoses, intratumoral necrosis, and hemorrhage are also common findings (UCHIDA et al, 1998;KOESTNER et al, 1999;BERROCAL et al, 2005). The origin and type of this tumor were determined by immunohistochemical evaluation, which indicated that the cells originate from the neuroectodermal tissue within the nasal cavity (WILSON; DUNGWORTH, 2002).…”

“…They are classified as cerebellar (known as medulloblastoma) and extracerebellar. The extracerebellar tumors are further divided into central (cPNET) and peripheral (pPNET) types (KOESTNER et al, 1999). In humans, PNETs consist of neoplasms of the Ewing's sarcoma family (WINDFUHR et al, 2004).…”

Case of a miniature dachshund with a primitive neuroectodermal tumor confined to the forebrain region treated with a combination of surgery and chemotherapy

“…Non-cerebellar PNETs can arise within the central nervous system or peripherally in the soft tissues or bone (peripheral PNETs). In veterinary medicine, non-cerebellar PNETs have been reported in dogs [1, 3, 4, 6, 7, 15], with five of these studies involving magnetic resonance imaging (MRI). Non-cerebellar PNETs confined intracranially have only been reported for two dogs [1, 4], and only one of these reports [1] provided clinical information regarding treatment by surgical resection.…”