We present the case of a 23-year-old woman with a long-standing history of recurrent left-sided pleural effusion unrelated to her menstrual cycle. At her last presentation, non-contrast-enhanced chest CT showed a pleural effusion and a lower left hemithorax mass, both large enough to cause complete collapse of the lower lobe and partial collapse of the upper lobe. Thoracoscopic surgery revealed a multilobulated mass originating from the dome of the diaphragm with pleural deposits. Histopathology diagnosed this as a calcifying fibrous tumour of the pleura, a rare benign tumour with excellent prognosis when completely excised.