RESUMO
Cystic lymphangioma mainly occurs in children and develops from the lymphatic vessels. The present study reports the case of a 36-year-old female patient with a giant cystic mediastinal lymphangioma. She was asymptomatic and the diagnosis was accidental. Imaging studies are important for referral to the Cardio-Thoracic Surgery Department for surgical intervention in order to remove the lesion. It is important that in the case of an enlargement of the mediastinum observed in a thoracic X-ray, the possible diagnosis takes into consideration various hypotheses. Early diagnosis may prevent further growth and infiltration of structures that hinder the surgical approach. LEARNING POINTS: Cystic lymphangioma corresponds to approximately 0.7 to 4% of all mediastinal tumours.They are usually asymptomatic and, in adults, the diagnosis is accidental.After an imaging study with computed tomography and nuclear magnetic resonance, patients are usually candidates for surgical excision.