We report an unusual case of 9.5-cm-sized embryonal rhabdomyosarcoma arose from a mediastinal mature teratoma in a 46-yr-old man. A man presented with chest trauma as a result of an accident at 10 September 2011. On chest X-ray, an anterior mediastinal mass was detected. To obtain further information, chest computed tomography (CT) with contrast enhancement was performed, revealing an anterior mediastinal mass. Complete surgical excision was performed and entire specimen was evaluated. Pathologic diagnosis was embryonal rhabdomyosarcoma arising in mature cystic teratoma. After surgical excision, two cycles of dactinomycin-based chemotherapy were performed. Lung metastasis was detected on follow up CT in September 2012, and wedge resection was performed. Pathological finding of the lung lesion showed same feature with that of primary rhabdomyosarcoma.
Antibiotics, Antineoplastic/therapeutic use ; Dactinomycin/therapeutic use ; Desmin/metabolism ; Humans ; Immunohistochemistry ; Lung Neoplasms/radiography/secondary/surgery ; Male ; Mediastinal Neoplasms/*diagnosis/pathology ; Middle Aged ; Neoplasms, Germ Cell and Embryonal/drug therapy/*radiography/surgery ; Rhabdomyosarcoma, Embryonal/drug therapy/*radiography/surgery ; Teratoma/*diagnosis/pathology ; Tomography, X-Ray Computed

The association of hematological malignancies with a mediastinal germ cell tumor (GCT) is very rare. We report one case of a young adult male with primary mediastinal GCT who subsequently developed acute megakaryoblastic leukemia involving isochromosome (12p). A 25-yr-old man had been diagnosed with a mediastinal GCT and underwent surgical resection and adjuvant chemotherapy. At 1 week after the last cycle of chemotherapy, his peripheral blood showed leukocytosis with blasts. A bone marrow study confirmed the acute megakaryoblastic leukemia. A cytogenetic study revealed a complex karyotype with i(12p). Although additional chemotherapy was administered, the patient could not attain remission and died of septic shock. This case was definitely distinct from therapy-related secondary leukemia in terms of clinical, morphologic, and cytogenetic features. To our knowledge, this is the first case report of a patient with mediastinal GCT subsequently developing acute megakaryoblastic leukemia involving i(12p) in Korea.
Adult ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use ; Bleomycin/administration & dosage ; Bone Marrow/pathology ; *Chromosomes, Human, Pair 12 ; Cisplatin/administration & dosage ; Etoposide/administration & dosage ; Humans ; Isochromosomes ; Karyotyping ; Leukemia, Megakaryoblastic, Acute/drug therapy/etiology/*genetics ; Male ; Mediastinal Neoplasms/*diagnosis/drug therapy/surgery ; Neoplasms, Germ Cell and Embryonal/*diagnosis/drug therapy/surgery ; Neoplasms, Second Primary/drug therapy/etiology/*genetics ; Republic of Korea ; Shock, Septic/pathology