Contemporary options and future perspectives: three examples highlighting the challenges in testicular cancer imaging

Abstract

Purpose: One of the main issues in testicular germ cell tumors (TGCTs) management is to reduce the necessary amount of treatment to achieve cure. Excess treatment burden may arise from late diagnosis of the primary as well as from false positive or negative staging results. Correct imaging is of paramount importance for successful management of TGCT. The aim of this review is to point out the current state of the art as well as innovative developments in TGCT imaging on the basis of three common challenging clinical situations.

Methods: A selective literature search was performed in PubMed, Medline as well as in recent conference proceedings.

Results: Regarding small testicular lesions, recent studies using elastography, contrast-enhanced ultrasound or magnetic resonance imaging (MRI) showed promising data for differentiation between benign and malignant histology. For borderline enlarged lymph nodes FDG-PET-CT performance is unsatisfactory, promising new techniques as lymphotropic nanoparticle-enhanced MRI is the subject of research in this field. Regarding the assessment of postchemotherapeutic residual masses, the use of conventional computerized tomography (CT) together with serum tumor markers is still the standard of care. To avoid overtreatment in this setting, new imaging modalities like diffusion-weighted MRI and radiomics are currently under investigation. For follow-up of clinical stage I TGCTs, the use of MRI is non-inferior to CT while omitting radiation exposure.

Conclusion: Further efforts should be made to refine imaging for TGCT patients, which is of high relevance for the guidance of treatment decisions as well as the associated treatment burdens and oncological outcomes.

Keywords: Germ cell tumors; Imaging; Non-seminoma; Seminoma; Small testicular masses; Staging; Testicular cancer.

Fig. 1

B-mode with Doppler and CEUS ultrasound in small testicular lesions. Case 1(Fig. 1a and 1b): Testicular B-mode grayscale ultrasound with a small homogenous, hypoechogenic lesion (a, white arrow) in an 28 year old patient, (b) hypervascularization of this lesion (white arrow) in Doppler-Mode. Inguinal exploration confirmed seminoma histology. Case 2(Fig. 1c and 1d): Testicular B-mode grayscale ultrasound with an homogenous lesion and microlithiasis (c, yellow arrow) and CEUS with early contrast enhancement in after intravenous contrast agent administration (d, yellow arrow). (Pictures c and d are depicted from: “CEUS–use in testicular pathologies”, J. Macron, M. Trottmann, CG Stief, DA Clevert; Der Radiologe. 2018 Jun. 58(6):572–578. Springer-Verlag)

Fig. 2

Abdominal and thoracic FDG-PET-CT of an ambiguous retroperitoneal lymph node. a: abdominal CT-Scan. Figure b–d: FGD-PET-CT scan of abdomen/thorax/neck and head with an enlarged interaortocaval lymph node (green arrow) and intense FDG uptake in a patient with right sided seminoma and slightly increased lymph node after orchiectomy (Pictures from “Testicular cancer: Diagnosis and Initial Management”, Springer-Verlag)

Fig. 3

Abdominal FDG-PET/MRI of a retroperitoneal residual tumor in metastatic seminoma after chemotherapy. A: Inverted maximum intensity projection (MIP) of an whole-body PET/MRI with a paraaortal lymph node (green arrow). B: Transversal image of the abdominal PET/MRI in fusion sequence with high FDG uptake due to increased metabolism (green arrow). C: Transversal image of the abdominal PET/MRI in T1 sequence with hyperintens lymph node after contrast agent administration (green arrow). D: Transversal image of the abdominal PET/MRI in DWI sequence with hypointens lymph node (green arrow). E: Coronar image in T1 sequence with hyperintens lymph node after contrast