The Value of Bronchial Washings and Bronchoalveolar Lavage in the Diagnosis of Lymphangitic Carcinomatosis: Discussion
Diffuse interstitial pulmonary infiltrates in patients with underlying malignant disease has a wide differential diagnosis. Transbronchial lung biopsy has been advocated as being the procedure of choice for establishing the diagnosis. Ventilation-perfusion lung scan demonstrating an irregular peripheral perfusion defect has been suggested to be helpful in raising the suspicion of lymphangitic carcinomatosis but has poor specificity and undocumented sensitivity. Bron-choalveolar lavage is a safe, commonly used procedure which has been referred to as a “liquid biopsy of the lung.” A wide variety of inflammatory and infectious diseases have been documented by BAL, but its use in diagnosing neoplastic disease has been limited.
In this review, BAL confirmed the diagnosis of lymphangitic carcinomatosis in all patients in whom it was used. Routine bronchial washings yielded the diagnosis in a satisfactory 57 percent of patients (four of seven), and the combination of sputum, bronchial washing, or BAL confirmed the diagnosis in 75 percent (9/12). This yield could potentially have been increased if BAL had been used in all patients. Of importance is the finding that BAL confirmed lymphangitic carcinomatosis in all of the patients in whom transbronchial biopsy or brushing was precluded on the basis of coagulopathy or inability to cooperate. Moreover, the latter two procedures were found to be less sensitive than BAL in establishing the diagnosis. No complications with BAL were documented, while one patient had a significant pulmonary hemorrhage following transbronchial lung biopsy. Bronchial brushings did not provide any unique diagnostic information compared with bronchial washings and BAL. This retrospective study has demonstrated the value of BAL as a safe and relatively noninvasive method of confirming lymphangitic carcinomatosis. We therefore advocate that BAL be performed to confirm the diagnosis of lymphangitic carcinomatosis before proceeding to a biopsy and stress the value of BAL as the sole procedure when coagulopathy or other contrain-diction to biopsy is present.