title: Non-germ cell tumours arising in germ cell tumours (teratoma with malignant transformation) in men: CT and MR findings.
abstract: OBJECTIVE
  To describe the imaging findings of germ cell tumours (GCT) containing non-germ cell malignant components (also designated teratoma with malignant transformation or TMT).
  
  
  METHODS
  The records of 14 male patients with GCT and a non-germ cell histological component TMT were retrospectively reviewed. All patients had computed tomography (CT) and/or magnetic resonance (MR) studies before and after initial surgery and chemotherapy, as well as during follow-up. Imaging findings were correlated with the response to treatment and with overall survival. Pathological evaluation, immunohistochemistry, serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) were also taken into consideration. Sarcoma was identified in 10 out of 14 patients, with rhabdomyosarcoma ranking first (n=4), followed by osteosarcoma (n=2), fusiform cell sarcoma (n=1), undifferentiated sarcoma (n=1), neurosarcoma (n=1) and myxoid sarcoma (n=1). Other histological types of malignant transformation included adenocarcinoma (n=3) and bronchoalveolar carcinoma (n=1). Overall, 9 patients relapsed at a median time of 84 months (range 60-168).
  
  
  RESULTS
  Non-GCT malignant transformation was identified in the retroperitoneum (5), testis (3), mediastinum (3), peritoneum (2) and lungs (1). The CT and MR imaging findings before treatment and after relapse were evaluated with emphasis on imaging features that could possibly imply the presence of malignant transformation (heterogeneously enhancing soft-tissue masses, ossified masses with calcified lymph nodes, diffuse epiploic thickening associated with ascites and peritoneal nodules, pulmonary alveolar infiltration with septal thickening). All but 1 patient with TMT presented with nodal and distant metastases. The prognosis was poor: within a median follow-up of 59 months (range 3-180), 4 out of 14 patients were alive.
  
  
  CONCLUSIONS
  TMT is rare and associated with poorer survival compared to GCT. Imaging can be useful as CT and MR findings may suggest this entity and lead to an early biopsy and appropriate treatment.
authors.affiliation: Department of Radiology, Institut Gustave-Roussy, Villejuif, France. alexandra.athanasiou@curie.net
authors.forename: A
authors.initials: A
authors.lastname: Athanasiou
authors.forename: D
authors.initials: D
authors.lastname: Vanel
authors.forename: O
authors.initials: O
authors.lastname: El Mesbahi
authors.forename: C
authors.initials: C
authors.lastname: Theodore
authors.forename: K
authors.initials: K
authors.lastname: Fizazi
mesh_terms: D000328:Adult; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013724:Teratoma / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed; D055815:Young Adult