Pulmonary Pathology Online
Pathology of Adenoid Cystic Carcinoma of the Lung
carcinoma of the lung is a distinctive salivary gland-type malignant
neoplasm that arises infrequently as a primary tumour in the lung.
The incidence of primary adenoid cystic carcinoma of the lung is relatively rare.
The tumour is often located in the trachea or mainstem bronchus and presents as an endobronchial mass lesion.
Generally adenoid cystic carcinoma originates from the bronchial glands.
The tumour may cause bronchial obstruction with post obstructive atelectasis and pneumonia.
Grossly, most lesions are described as endobronchial and measure from 0.9 to 4.0 cm in greatest dimension.
Some cases, however, show poorly circumscribed infiltrative tumours.
The tumour demonstrates a variety of growth patterns which include - cribriform (cylindromatous), tubular, and solid.
Adenoid cystic carcinoma is generally regarded as a slow growing low-grade malignancy. However, this tumour has a high risk of incomplete resection because of its unique histological invasion patterns.
Disease stage at the time of diagnosis may play an important role in predicting the clinical outcome of patients with these tumors.
Despite their generally slow and indolent growth in other locations, adenoid cystic carcinoma arising in the lung may in certain cases be more aggressive with distant metastasis.
Immunohistochemical stains identify that the glandular component strongly reacts with broad-spectrum keratin stains and CEA, the myoepithelial component shows coexpression of keratin and actin filaments as well as variable expression of vimentin, S-100 protein, and GFAP.
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