Pulmonary Pathology Online
Pathology of Granular Cell Tumour of Bronchus
Granular cell tumor of the lung is a rare neoplasm comprising 6-10% of all
granular cell tumor.
It was first described in the bronchus by Kramer in 1939.
The tumour usually occurs in adults but a few cases have been reported in children.
These tumours are located in the trachea, bronchus or in the lung parenchyma.
Granular cell tumor is usually found during bronchoscopy performed because of symptoms of pneumonia, lung cancer and hemoptysis or dyspnea.
The tumour often presents as a polypoid mass obstructing the bronchus. The tumours are most often solitary , but in some cases there may multiple lesions.
Pulmonary granular cell tumour behave in a benign fashion.
It has been observed that tumours of less than 8 mm are more amenable to endoscopic removal and larger tumors are more likely to infiltrate through the bronchial wall.
Histologically, the endobronchial granular cell tumour consisted of submucosal infiltrates of round to oval cells with distinct cell borders, abundant granular cytoplasm and eccentrically placed small round nuclei.
In some cases the cells resemble signet-ring cells.
The tumour often infiltrate into peribronchial tissue and in some cases focally infiltrate an adjacent lymph node.
Hyalinized thickening of the subepithelial basement membrane is common.
The overlying epithelium often show squamous metaplasia or ulceration.
There is usually no evidence of cellular atypia , necrosis, hemorrhage and mitotic activity.
The tumours are positive for S-100 protein, neuron specific enolase, KP1 (CD68) and vimentin.
The tumours do not express desmin, keratin or p53 oncoprotein.
Complete surgical excision is the treatment of choice.
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