Background: Large sized anterior mediastinal masses can be a challenge in thoracic surgery due to the anesthesiological risks. The management of these tumors requires a surgical biopsy to get sufficient tissue for histopathological and immunohistochemical analysis, which are essential for a precise diagnosis and target treatment.

Case description: We report the case of a 45-year-old woman with a persistent cough and fatigue lasting 2 months. A chest computed tomography (CT) scan revealed a large anterior mediastinal mass. An initial biopsy diagnosed this patient with myeloid sarcoma. However, a further biopsy of fresh tissue was necessary to characterize the tumor to initiate targeted treatment. To avoid complete airway obstruction and cardiovascular collapse due the compression of the anterior mediastinal mass during general anesthesia, we performed a Chamberlain procedure on an awake patient using hypnosis and local anesthesia.

Conclusions: Anterior mediastinotomy according to Chamberlain approach allowed the retrieval of sufficient fresh tissue for an accurate immunohistochemical diagnosis, while avoiding more invasive and traumatic surgical approaches such as sternotomy. This approach is particularly valuable in high-risk patients where general anesthesia could exacerbate airway or cardiovascular collapse. In this context the procedure was successfully performed under local anesthesia and hypnosis in selected patients to avoid anesthesiological risks due the compression that anterior mediastinal mass can exert.