P322 : Empyema necessitatis that needs delicate diagnostic approach in dermatology

Empyema necessitatis (EN) refers to extension of a pleural infection out of thorax and into the neighbouring chest wall and surrounding skin. EN has received little attention from a dermatological point of view but it is essential to recognize it because of the possibility of causing mortality if not treated properly and in time. We report a 50-year-old man, with a soft erythematous enlarging mass on the right lower thoracic wall. He had a past history of right pneumonectomy due to lung cancer. Chest soft tissue culture showed methicillin-resistant Staphylococcus aureus as the main etiological agent of his empyema “necessitatis”. He was treated with multiple surgical procedure composed of massive normal saline irrigation and wound closure. Enlarging and painful subacute thoracic mass with fluctuation is usually considered as simple abscess or infected epidermal cysts, and so apt to be managed through incision and drainage without imaging study. EN can be the alarm sign to such a simple approach. EN suspicious lesion must include diagnostic evaluation such as chest X-ray and computed tomography scan to rule out lung infection. Dermatologists should know about this entity in order to avoid malpractices such as late diagnosis and improper treatment for this potentially life-threatening disease.