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Cytologic and immunohistochemical characterization of a primitive neuroectodermal tumor in the brain of a dog
Author(s) -
Choi Ul Soo,
Philippe Labelle,
Alleman A. Rick,
Kim Min Su,
Lee Ki Chang
Publication year - 2012
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/j.1939-165x.2012.00404.x
Subject(s) - pathology , immunohistochemistry , cytology , primitive neuroectodermal tumor , biology , medicine
A 6‐year‐old intact female P ointer 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 CD 3 nor CD 79a. 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 CD 45 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.