Granular cell tumour affecting the left vocal cord in a dog.
Granular cell tumours (GCTs) have been described in human vocal cords, but not in those of the dog. A single polyp in the left vocal cord, associated with laryngeal oedema and monolateral hyperplasia of the tonsil, was observed endoscopically in a 6-year-old male dog. Cytologically, the mass was characterized by well-defined polygonal cells, with granular cytoplasm and an eccentric nucleus. Histologically, the mass showed sheets of globoid to polygonal cells, filled with numerous diastase-resistant, periodic acid-Schiff-positive granules, and scanty stroma. Ultrastructurally, the granules were represented by heterogeneous lysosomes of variable size, suggesting a diagnosis of GCT. As reported in man, hyperplasia of the laryngeal and tonsillar epithelium and the presence of foci of pearl-like epithelial cells, mimicking invasive squamous cell carcinoma, were observed. Immunohistochemical examination revealed labelling of neoplastic cells for S-100 protein, CD68, collagen IV, and, focally, for glial fibrillary acidic protein, neuron-specific enolase and vimentin. These findings suggested a Schwann cell origin of the GCT.
Rossi
G
G
Department of Animal Science, University of Camerino, Via Circonvallazione 93/95, 62024 Matelica, Italy. giacomo.rossi@unicam.it
Tarantino
C
C
Taccini
E
E
Renzoni
G
G
Magi
G E
GE
Bottero
E
E
D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D004724:Endoscopy / Q000662:veterinary; D016586:Granular Cell Tumor / Q000473:pathology / Q000662:veterinary*; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000473:pathology / Q000662:veterinary*; D008297:Male; D014827:Vocal Cords / Q000473:pathology*