Metastatic metaplastic carcinoma of the breast: diagnosis by bronchial brush cytology

Metaplastic carcinoma of the female breast is an uncommon lesion that may metastasize to body sites. To our knowledge, this is the first reported case of pulmonary metastasis diagnosed on bronchial brush cytology. The patient presented with pulmonary symptomatology 1 yr and 3 mo after a left modified radical mastectomy for breast carcinoma. Bronchoscopic examination revealed an endobronchial lesion partially obstructing the bronchus intermedius. Bronchial brush cytology showed the presence of nonkeratinizing squamous tumor cells admixed with a few scattered clusters of tumor cells with glandular features. Histologic review of the original breast lesion showed a metaplastic carcinoma of the breast with a predominant squamous-cell component. Accurate knowledge of a patient's clinical history is necessary to differentiate a second primary lesion from a metastatic one, particularly when the original lesion is so uncommon.