Immunoreactivity in granular cell tumours of the larynx.

OBJECTIVE: To elucidate histogenesis and behaviour of laryngeal granular cell tumours (GCT) and to determine the role of p53 protein expression in these lesions. METHODS: The clinical, pathological and immunohistochemical findings of three cases of laryngeal GCTs are described. RESULTS: All tumours were surgically excised and appeared histologically benign. Pseudoepitheliomatous hyperplasia, mitosis and nuclear pleomorphism were not found in any of the three cases. All lesions were negative for keratin 8, desmin and actin. Only one case stained for collagen IV. Positive staining was found for S-100 protein and CD68 in all tumours. Ki-67 and Bcl-2 staining was confined to occasional cells. p53 reactivity was seen in all tumours; positivity ranged from 35 to 42%. The three patients have remained free of disease without complications up to 10 years after treatment. CONCLUSION: Immunohistochemical findings support benign behaviour and a Schwann cell origin for laryngeal GCT. The expression of p53 by granular cells is unclear but appears to be unrelated to behaviour.