Bronchoalveolar carcinoma of the lung


Increasing in incidence over the last three decades.

2-5% of non-small cell lung cancers.

Proportionately more patients are women and nonsmokers than with other forms of lung cancer.

Pathologic finding of lepidic growth, the spread along alveolar septa without lung destruction.

A specific type of adenocarcinoma that grows along preexisting alveolar structures without stromal, vascular or pleural invasion.

Often presents as a mixture of adenocarcinoma and bronchoalveolar carcinoma.

A component of this lesion may be seen in up to 20% of NSCLC cases.

Usually well differentiated, originate distal to bronchi, proclivity for lymphatic and aerogenous spread and tendency to grow across intact alveolar septa.

Better prognosis than other similar staged non-small cell cancers of the lung.

Two subtypes exist: mucinous and nonmucinous.

The nonmucinous variant occurs in 40 to 60% of cases and pains to present as a solitary peripheral nodule.

Immunochemistry similar to conventional adenocarcinoma, nonmucinous lesion is cytokeratin 7 and thyroid transcription factor 1 (TTF1) positive and cytokeratin 20 negative.

The nonmucinous type is often dependent on EGFR pathway mutations and therefore sensitive to targeted treatments.

35-39% present with Stage I disease.

Bronchorrhea, the expectoration of copious quantities of sputum, is an uncommon but characteristic clinical feature.

Radiographic findings include ill-defined consolidation or ground-glass opacities that occur in a focal or multilobar distribution.

Lymphadenopathy and pleural effusion occur occasionally.

High-resolution CT manifestations are numerous and include alveolar consolidation and ground-glass attenuation, which occasionally manifest as a crazy-paving pattern.

The ground-glass attenuation reflects the low-density intraalveolar material of glycoprotein, whereas the superimposed reticular attenuation is due to infiltration of the interstitium by inflammatory or tumor cells.

Tendency for intrapulmonary spread and limited regional nodal involvement with bronchioloalveolar carcinoma, and a reduced tendency for extrathoracic metastases.

Cough is the most common presenting process and is seen in about one third of patients.

Among patients with stage IIIB/IV non-small cell lung cancers median survival is about 15 months.

Divided into mucinous (41%-60%) and nonmucinous (21-45%) forms with the latter type associated with an improved prognosis.

Bronchorrhea a late manifestation of disease in 5% of patients.

Radiologic manifestations include a solitary peripheral nodule, airspace disease, and multiple pulmonary nodules, 43%, 30%, and 27%, respectively.

Airspace disease is the second most frequent form of presentation.

70% cure rate in patients with localized disease and <3cm.

Death usually secondary to respiratory failure in the setting of diffuse pulmonary involvement or intercurrent lung infection rather than from spread of disease to other organs.

PET scans are not optimal for imaging this malignancy.

Patients have a high response to epithelial growth factor receptor tyrosine kinase inhibitors erlotinib and gefitinib.

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