A Case Series of Transformation of Teratoma to Primitive Neuroectodermal Tumor: Evolving Management of a Rare Malignancy
A 33 year-old man underwent right radical orchiectomy after presenting with severe back pain and right testicular swelling. A pre-operative computed tomography (CT) of the chest, abdomen, and pelvis revealed extensive retroperitoneal lymphadenopathy, including a confluence of tissue measuring 9.7×7.4 cm, as well as scattered mediastinal lymphadenopathy. His pathology demonstrated a mixed GCT composed of embryonal carcinoma (40%), teratoma (40%) and yolk sac tumor (20%). Surgery was followed by three cycles of bleomycin, etoposide and cisplatin (BEP). Follow-up imaging revealed a response to chemotherapy, however his disease persisted in the retroperitoneal lymph nodes. He then underwent retroperitoneal lymph node dissection (RPLND), which showed metastatic mature teratoma in multiple lymph nodes without any residual GCT.\nSix weeks following RPLND, he presented with acute kidney injury, fatigue, and an LDH >20,000 U/L. Imaging studies showed widespread recurrent disease, including supraclavicular lymphadenopathy, a new right inguinal soft tissue mass and an enlarging conglomerate of retroperitoneal lymphadenopathy in the para-aortic region (). The supraclavicular node was biopsied, which demonstrated a poorly differentiated high grade neoplasm though the definitive diagnosis remained in question. As a result, his original tumor and the RPLND specimens were reviewed at another institution in conjunction with the supraclavicular specimen. Upon further review, his original tumor was deemed primarily PNET (80%) with teratoma (10%), yolk sac tumor (8%) and embryonal carcinoma (2%). The RPLND, as well as the supraclavicular lymph node biopsy, confirmed PNET in both specimens ().\nThe patient was not initially a candidate for surgical resection. Therefore, neoadjuvant chemotherapy with VAC/IE was initiated. During his first cycle of chemotherapy, he developed ifosfamide-induced encephalopathy and renal tubular acidosis. As a result, the IE component of this regimen was held for his subsequent treatment and he received an additional four cycles of VAC thereafter.\nAt completion of his neoadjuvant chemotherapy, his imaging studies demonstrated complete response in his neck and mediastinal lymphadenopathy and partial response of his retroperitoneal lymphadenopathy () and right inguinal mass. Subsequently, the patient underwent repeat RPLND and excision of the right inguinal soft tissue mass. Pathology of both specimens showed extensive necrosis with rare atypical cells consistent with PNET. Adjuvant chemotherapy was not administered after surgery since the patient has already received maximum cumulative dosing of doxorubicin and due to his history of ifosfamide-induced encephalopathy. His last imaging studies two months after his surgery showed no recurrent disease.