Aim: The aim of this case was a correct diagnosis of mediastinal tumor in a 41-years old female patient. Introduction: The rarity of primary extraneural ependymomas, its great variations in morphology and rare occurrence of metastasis, increase chances of misdiagnosis. Case report: Macroscopic examination of received specimen was performed, followed by histological and immunohistochemical analysis of the tissue samples. In presented case, onset of the disease was 14 years ago, when after right salpingo-oophorectomy, patient was diagnosed with malignant mesothelioma. In following years patient had multiple and extensive surgical procedures, resulting in different patohistological diagnosis, and after seven years, a diagnosis of extraneural ependymoma was established. Later on, patient was surgically treated in several medical centers across the region, again with different patohistological diagnosis. At present, tumor metastasized to mediastinum, presenting as grey to brown, multicystic formation, with cysts filed with clear serous fluid or red-brown hemorrhagic fluid. Inner surface of the cysts had smooth to partly papillary appearance. Tumor cells exhibited several architectural paterns (solid, pseudorosette or rosette formations, papillary and pseudopapilary structures), and immunophenotype specific for extraneural ependymoma (GFAP, ER, PR positive, calretinin, WT-1, S100, synaptophysin, chromogranin, CK7 and pan-cytokeratin negative). Conclusion: This case demonstrates an important principle in tumor pathology. Neoplasms may occur in unusual and unexpected primary and metastatic sites. Pathologists need to be familiar with histologic features of a wide range of neoplasms and not just the appearance of neoplasms within their own limited subspecialty area.

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