An uncommon chest mass: oleothorax

We would like to report a case of unilateral oleothorax, which generated great diagnostic difficulties and was initially interpreted as a lung mass, probably of neoplastic origin. An 84-year-old woman presented with a dry cough that had persisted for four months. A chest X-ray showed a mass in the right hemithorax (Figure 1A). Due to the suspicion of lung cancer, the patient underwent CT, and the scans demonstrated a posteriorly heterogeneous mass in the upper right hemithorax (Figure 1B). Aspirated viscous pleural fluid proved to be mineral oil. Upon further discussion, the patient vaguely remembered that she had been treated for tuberculosis and had received an oil injection 60 years prior.