Rubina Malik1, Dhanya Mullassery2, Maren Kleine-Brueggeney3, Ayad Atra1, Anami Gour4, Robin Sunderland3, Bruce Okoye2
1Department of paediatric oncology, St George's Hospital, London, United Kingdom. 2Department of paediatric surgery, St George's Hospital, London, United Kingdom. 3Department of paediatric anaesthesia, St George's Hospital, London, United Kingdom. 4Department of paediatric ntensive care, St George's Hospital, London, United Kingdom

Background - Anterior mediastinal masses (AMM) pose diagnostic challenges of exaggerated cardiorespiratory risks during anaesthesia for biopsy. We reviewed our institutional practice to assess the safety of our approach. Methods - Retrospective review of patients with AMM at a single tertiary paediatric surgical oncology centre (January 2011 -December 2016). Data analysed on clinical presentation, mode of tissue diagnosis, anaesthetic techniques and complications. Results – Of the 44 patients (median age 11 years, 27 male) admitted with AMM, 22 had respiratory symptoms. Imaging confirmed tracheobronchial compression in 26 children. Histology included Hodgkin’s lymphoma (16), non-Hodgkin’s lymphoma (14), leukaemia (9), lipoblastoma (1), teratoma (1), PNET (1), rhabdomyosarcoma (1) and mediastinal metastasis from nasopharyngeal carcinoma (1). Twenty patients had a lymph node biopsy. Pleural fluid and peripheral blood film confirmed diagnosis in 4 and 7 patients respectively. Ten patients had image-guided core biopsy of mediastinal mass and 2 had mediastinoscopic biopsy of paratracheal lymph node. One patient with likely metastatic recurrence of a relapsed ethmoid carcinoma did not have tissue diagnosis. We assessed the 25 anaesthetics performed in our hospital. Spontaneous breathing was maintained in 18 patients (2 had pressure support or CPAP, 3 had supraglottic airway) and 7 controlled ventilation (6 with an endotracheal tube). Spontaneous breathing patients had ketamine (13), ketamine and midazolam (3), ketamine and propofol (1), propofol (1), inhalation anaesthetic (2) and local anaesthesia (1). There were no anaesthetic complications. There were 11 planned PICU admissions. Four patients needed admission to PICU for tumour lysis syndrome. Two patients needed a repeat node biopsy (1 post steroid and 1 inadequate sample). Conclusion- Safe tissue diagnosis of anterior mediastinal masses can be obtained by a personalised multidisciplinary approach. Use of alternative tissues, local anaesthesia and ketamine sedation helps reduce the need for general anaesthetic, muscle paralysis and controlled ventilation.