Mediastinal mixed germ cell tumour

Case contributed by Jack Ren

Patient Data

Age: 20
Gender: Male

CXR show a large lobulated mass in the anterior mediastinum.

CT shows mediastinal soft tissue density mass lesion. The lesion is not enhanced by contrast & has a hypodense core. The adjacent lungs demonstrate some compressive atelectasis. 

Case Discussion

The patient when on surgical removal of the mediastinal mass as well as with 4 regional lymph nodes and pleural nodule.



Mediastinal mass: Sections  show  a  non-seminomatous   mixed  germ cell  tumour  showing extensive tumour necrosis.  The percentage of viable tumour is estimated at  20%.  100% of  viable  tumour is  yolk  sac tumour   showing a  variety of patterns including some cystic areas  with hylaine globules in cells lining a cyst.  Schiller-Duval bodies are readily identified.  The left-sided soft grey nodule is a keratin-filled cyst surrounded by entirely necrotic tissue consistent with entirely necrotic teratoma.  No immature teratoma component is identified.   A  few foci  showing  larger  more  pleomorphic  cells are present which  are the  pleomorphic  cell type  pattern of yolk  sac tumour (alpha feto-protein  positive,  CD30 and  beta-HCG negative).   There is no evidence of embryonal carcinoma,  seminoma or choriocarcinoma on routine or immunohistochemistry stains. Alpha feto-protein stain shows only a few foci of positivity within the  yolk sac tumour.

Pleural nodule: Sections  show both viable  and necrotic  yolk sac tumour  with a small amount of attached  diathermied skeletal  muscle.  Focally  viable yolk sac tumour abuts an inked margin immediately adjacent to an area of diathermied margin, over a distance of approximately 5 mm

Lymph nodes: no viable tumour


  1. Mediastinal tumour - non-seminomatous mixed germ cell tumour.
  2. Approximately 20% of tumour viable.
  3. 100% of viable  tumour is  yolk sac tumour.   Entirely  necrotic teratoma also  present.  No  immature  teratoma   identified.
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Case information

rID: 24414
Published: 14th Aug 2013
Last edited: 25th Nov 2015
System: Chest
Inclusion in quiz mode: Included

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