Childhood pulmonary langerhans cell histiocytosis in bronchoalveolar lavage: A case report along with review of literature.

Isolated pulmonary Langerhans cell histiocytosis (LCH) is rare in childhood, and few cases have been diagnosed on bronchoalveolar lavage (BAL) smears. We hereby report a child with cystic lesions in both lungs diagnosed as LCH on BAL smears and compare the cytomorphologic findings with BAL smears of five patients with various pathologies. The BAL smears of the index case showed numerous macrophages with many atypical histiocytes showing coffee bean-shaped nuclei, nuclear grooving along with few giant cells. Immunocytochemistry for S-100 protein and CD1a was positive in these cells (16.5%). The mean percentage of macrophages showing nuclear grooving, bi-nucleation, and multinucleation was much higher in the case with LCH compared to the other cases. Review of literature and the present case study shows that in the presence of appropriate radiologic findings, characteristic morphologic features and demonstration of 5% or more CD1a positive cells in BAL is strongly suggestive of pulmonary LCH. Diagn. Cytopathol. 2016;44:1102-1106.