Utility of Flow Cytometry of Bronchoalveolar Lavage in the Diagnosis of T and NK Cell Malignancies in Critically Ill Patients.

OBJECTIVE The value of bronchoalveolar lavage (BAL) in the diagnosis of pulmonary diseases of diverse etiologies is widely accepted. Cytospin and cell-block preparations for cytomorphological (CM) evaluation and for immunohistochemical studies are the standard method to evaluate BAL, though it may be time-consuming. Flow cytometric (FC) evaluation, on the other hand, has a short turnaround time, and is a useful methodology to differentiate reactive processes from hematological neoplasms, or detect a small aberrant population in an inflammatory background. BAL specimens provide an excellent source for FC studies. CASE REPORTS We describe two cases of critically ill patients with no history of hematolymphoid neoplasms, who presented with non-specific symptoms. Abnormal pulmonary imaging studies prompted bronchoscopic evaluation and collection of BAL during the initial evaluation. FC analysis of the BAL fluid aided to the early diagnosis of aggressive NK cell leukemia and adult T cell leukemia/lymphoma, respectively. CONCLUSIONS Flow cytometric immunophenotyping in addition to the CM assessment increases the diagnostic value and provides timely diagnosis from BAL specimens, which is especially important for critically ill patients.