Mediastinal Germ Cell Tumor Exhibiting a Discrepancy between Tumor Markers and Imaging: A Case Study.
We report a mediastinal germ cell tumor (GCT) that exhibited a discrepancy between the time course of serum human chorionic gonadotropin (hCG) levels and clinical consequences. An otherwise healthy man, aged 34 years, was diagnosed with a nonseminomatous GCT, most likely embryonal carcinoma (EC), based on a mediastinal tumor biopsy. Standard chemotherapy resulted in an optimal decrease in serum hCG levels. However, multiple lesions in the liver continued to enlarge, which led to his death. Autopsy revealed few viable tumor cells in the liver, with the great majority of the tumor cells appearing to have undergone necrosis, suggesting that they responded to the chemotherapy. The residual tumor cells in the mediastinum and the liver were similar to syncytiotrophoblast cells, suggesting a cho-riocarcinoma (CC). On immunohistochemical analysis, the mediastinal tumor cells in the diagnostic biopsy specimen expressed both CD30 and hCG, whereas residual mediastinal and hepatic tumor cells in the autopsy specimen after chemotherapy also expressed hCG, but not CD30. These findings suggested that the patient suffered from a primary mixed GCT consisting of an EC and a CC. Both pre- and postchemotherapy tumors strongly expressed matrix metalloproteinase-2, supporting the aggressive and invasive features of the tumor phenotype. We speculate that the extremely invasive tumor destroyed normal liver structure, whereas chemotherapy and central necrosis reduced the number of viable cells themselves, causing a discordant decrease in serum hCG levels.
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan.
Kei
K
Takenaka
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan ; Cancer Center, Kobe University Hospital, Kobe, Japan.
Toru
T
Mukohara
Department of Diagnostic Pathology, Kobe University Hospital, Kobe, Japan.
Chihoko
C
Hirai
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan.
Yohei
Y
Funakoshi
Integrated Clinical Education Center, Kobe University Hospital, Kobe, Japan.
Yukiko
Y
Nakamura
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan.
Naoko
N
Chayahara
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan.
Masanori
M
Toyoda
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan.
Naomi
N
Kiyota
Department of Diagnostic Pathology, Kobe University Hospital, Kobe, Japan.
Tomoo
T
Itoh
Division of Pathology, Department of Pathology, Kobe University Graduate School of Medicine, Kobe, Japan.
Hiroshi
H
Yokozaki
Division of Medical Oncology/Hematology, Department of Medicine, Kobe, Japan ; Cancer Center, Kobe University Hospital, Kobe, Japan.
Hironobu
H
Minami
Liver metastasis; Matrix metalloproteinase-2; Nonseminomatous germ cell tumor; Serum human chorionic gonadotropin