Malignant Transformation of Testicular Teratoma to PNET, Adenocarcinoma, and Osteosarcoma with Complete Remission after Surgery and Combination Chemotherapy in a Young Adult Male

Abstract

Mixed germ cell tumors (GCT) with teratoma components can transform into somatic malignancies which can include histologies outside of traditional germ cell lineages. We describe a case of an 18-year-old man with a metastatic testicular GCT with both mature and immature teratoma components containing malignant transformation into multiple histologies including PNET in the primary testicular tumor and osteosarcoma in a separate pulmonary metastatic lesion. Management with targeted chemotherapy resulted in a durable remission. This is the first reported case that we know of a patient with primary PNET malignant transformation with subsequent metastatic transformation to osteosarcoma.

Testicular Mixed Germ Cell Tumor Combined with Malignant Transformation to Chondrosarcoma: A Very Rare and Aggressive Disease

“…Several studies demonstrated chemoresistance in patients with transformed histology to Cisplatin-based chemotherapy regimens [ 11 , 13 ] that are usually associated with good outcomes in non-transformed malignant germ cell tumors. It was also suggested that chemotherapy should be adapted and targeted against the most aggressive histology for better outcome and disease control [ 5 , 13 ]. However, there is still no consensus regarding the optimal treatment of mixed non-seminomatous GCTs with malignant transformation [ 14 ], and further research is needed to establish clear treatment guidelines.…”

“…Somatic type malignant transformations (SMTs) in mixed GCTs is a well-known phenomenon, but is very rare. It occurs in around 3-6% of these tumors and is believed to develop as a result of malignant transformation of the teratomatous components, although other mechanisms might exist such as abnormal differentiation of primordial germ cells [2,5,6]. Tumors accompanied by malignant transformation are more likely to metastasize at presentation and have further aggressive potential than those without this phenomenon [7].…”

Successful management of testicular primitive neuroectodermal tumor with multiple bone metastases

“…Among them, sarcoma and PNET are the most frequent histologies 1 . Cisplatin‐based chemotherapy regimens have proven to be ineffective in the treatment of teratoma with malignant transformation, including PNET 3,4 . We herein describe a case of testicular PNET with para‐aortic lymph node and multiple bone metastases.…”

Hydroxyurea promotes TET1 expression and induces apoptosis in osteosarcoma cells

“…Osteosarcoma (OS) is the most common type of bone cancer in both adolescents and young adults [1]. Abnormal epigenetic modifications, such as DNA methylation, have been observed in OS cells [2,3].…”