Growth of rhabdomyosarcoma colonies from pleural fluid

Pleural fluid from a child previously treated for rhabdomyosarcoma produced colonies in vitro. Cells from these colonies appeared to have the light and electron microscopic appearance of rhabdomyosarcoma cells. In this case, the malignant nature of the effusion had been suspected because of the patient's previous history; however, this technique may prove useful in the diagnosis of effusion of unknown etiology.