Introduction: Teratomas are tumours derived from pluripotent germ cells. They appear most frequently on ovaries. However, other locations are also possible: testicles, retroperitoneum, stomach, neck, and bottom of the mouth cavity. It is not very common to find teratomas in two different body cavities.
Case report: A 51-year-old patient visited her doctor complaining of an intensive pain which suddenly appeared in her low back. The computed tomography scan of the abdomen was performed, which revealed cystic formation, 12.5 x 18 cm in size, with remarkable capsule visualization. It had paraaortic, subdiaphragmatic, retropancreatic and suprarenal left localisation with signs of compression and pancreatic dislocation. The cystic formation had a septated appearance filled with clear fluid in all its parts except at the bottom, where it was dense. The intra-operative finding was left retroperitoneal mass placed above the left kidney, dislocating surrounding structures and their infiltration could not be excluded for sure. A tumour mass passed through the diaphragmatic hiatus and continued in the left thoracic space. The cyst was only drained and the fenestration was performed. Three months later, the second operation was performed--splenectomy, left suprarenaladenectomy, left nephrectomy, aortic deliberalisation, the left diaphragmatic crus was opened and tumour mass was completely removed from the thoracic space. The histological examination showed mature teratoma with morphological characterisations of the skin, so the definite diagnosis was dermoid cyst.
Conclusion: The patient presented with thoracoabdominal teratoma. Although without malignant transformation, the teratoma required splenectomy, supraadrenalectomy and nefrectomy due to its position and size.