case_images: PMC8008106_01
case_images: Histological features of germ-cell tumor (seminoma) with somatic malignant transformation (spindle cell sarcoma) (A) Classic seminoma (upper right corner) associated with spindle cell sarcoma (lower left corner), (H&E 200x). (B)
  in situ germ cell neoplasia (upper right corner) admixed with somatic spindle cell sarcoma (lower left corner), (H&E 200x). (C) Metastatic spindle cell sarcoma within the spermatic cord (H&E 200x). (D) The same field of picture C shows high proliferative Ki67 index (DAB 200x).
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case_images: F1
case_images: A high-grade malignant mesenchymal neoplasm with spindle cells was also found to be present, which probably originated from a malignant somatic transformation of the teratomatous component (Figures 1A,B). The microscopic morphology of the recurring inguinal lesion was the testicular high-grade sarcomatous component of the first testicular mass, according to the hypothesis that the inguinal lesion was a recurrence of the mesenchymal component (Figures 1C,D).
case_images: 18F-FDG PET/CT MIP and corresponding trans-axial images obtained at staging. (A) December 2016 before sarcoma therapy; (B) March 2017 after sarcoma therapy; (C) May 2017 early evaluation after two cycles of chemotherapy for GCT testicular cancer; (D) July 2017 at completion of GCT testicular cancer chemotherapy. Hypermetabolic left external iliac nodes (A, white arrow) show only slight decrease of uptake after sarcoma chemotherapy (B, white arrow) while they turn FDG-negative after chemotherapy for testicular cancer, respectively, after 2 cycles (C, white arrow) and 4 cycles (D, white arrow). Note bone marrow rebound after chemotherapy in B.
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case_images: F2
case_images: Tomography (PET) for suspicion of a new relapse. The FDG-PET scan showed high glucose uptake in multiple iliac adenopathies [max standardized uptake value (SUV) = 4.4; Figure 2A]. The subsequent abdominal-chest CT scan revaluation showed a substantial stabilization of the disease; however, FDG-PET revealed only a mild reduction in size and in glucose-uptake of the multiple iliac adenopathies (SUV max 3.7 vs. 4.4; Figure 2B). An early revaluation of the disease by FDG-PET after two cycles of therapy revealed a complete response of the disease with total disappearance of the previous uptakes (Figure 2C). A complete response was then confirmed by CT-PET (Figure 2D) and a chest-abdominal CT scan (Figure 3B), which was performed after the end of the treatment.
case_images: Diagnostic CT corresponding images at diagnosis and at therapy completion in (A,B), respectively.
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case_images: F3
case_images: CT scan was performed 1 month after surgery, which showed a liquid mass 6.7 cm in diameter in the right inguinal cavity and multiple bilateral iliac adenopathies (Figure 3A). Considering the metastatic stage of the disease, the patient was directed to receive systemic therapy. A complete response was then confirmed by CT-PET (Figure 2D) and a chest-abdominal CT scan (Figure 3B), which was performed after the end of the treatment.
case_images: Figure showcasing a timeline with relevant data of the clinical history of patient.
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case_images: F4
case_images: A timeline with the relevant data of this patient is shown in Figure 4.
case_images: Principal component analysis of seminoma, mixed germ cell tumors and sarcoma publicly available in The Cancer Genome Atlas project (TCGA) and our primary tumor and relapse in sarcoma.
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case_images: F5
case_images: TMT is more similar to sarcoma (Figure 5). These observations, which clearly agree with the histological diagnosis, suggested that the complete response of TMT after the PEB protocol cannot be explained by the global expression profile itself.