Conclusion
In summary, primary mediastinal immature teratoma with somatic-type
malignancy is extremely rare with extremely poor prognosis. When
laboratory and imaging findings are conflicting for patients with
immature teratoma after chemotherapy, somatic-type malignancy should be
considered. Due to its rarity, comprehensive reporting of clinical,
radiological and pathological features is needed for a diagnosis of an
immature teratoma with SM. We reported a primary giant mediastinal
immature teratoma with sarcoma and squamous malignant transformation
which was resistant to chemotherapy and radiotherapy but resected
completely. Rare as it is, additional cases of this pathology are needed
to add to the literature for a better understanding of somatic-type
malignancy and management of this disease.