Pathology of the extrapleural space: Keys to diagnosis

The extrapleural space (EPS) is a virtual anatomical space located at the periphery of the thorax, between the inner surface of the ribs and the parietal pleura. It can be affected by various pathological processes, including inflammatory disorders, infections, trauma and neoplasms. Given it is a small and relatively unfamiliar space for radiologists, its pathology is often mistaken for pleural or chest wall disease. Computed Tomography (CT) plays a key role in its evaluation. This article aims to highlight key, practical points for recognising the EPS and the conditions that affect it, helping reduce diagnostic and treatment errors often caused by confusion with pleural or chest wall diseases.