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Teratoma with malignant transformation


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A teratoma with malignant transformation (TMT) is a tumor that develops from germ cells when they grow and divide abnormally, forming a mass.  Approximately 6% of teratomas develop into TMTs by a process called malignant transformation, when some of the cells in the teratoma become cancerous.  TMTs can occur anywhere in the body, but most are located in the testes in men or ovaries in women.  The cause of TMT is unknown.  Treatment may include surgery and chemotherapy.[1]
Last updated: 9/21/2012
Because teratoma with malignant transformation (TMT) is quite rare, there are no established treatment guidelines.  In general, treatment often includes surgery to remove as much of the TMT as possible.  Chemotherapy that is specifically designed to target the malignant part of the TMT may also be used.[2][1]
Last updated: 9/21/2012
Prognosis depends on the extent of disease and effectiveness of surgery; it is best when teratomas with malignant transformation (TMTs) have not spread to other parts of the body (metastasized) and when surgery successfully removes all of the tumor cells.[2][3]  One article states that up to 60% of individuals diagnosed with teratoma with malignant transformation are alive five years after diagnosis.  The authors of this article also state that it is not known if the particular type of the malignant component changes prognosis.[2]
Last updated: 9/21/2012

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  • Is someone diagnosed with teratoma with malignant transformation (TMT) considered to have cancer?  If so, is it the type of cancer within the teratoma or is TMT a cancerous classification? See answer

  • I am trying to find out more information about teratomas with malignant transformation, specifically related to prognosis.  I had a single mass removed with clean margins and no infiltration.  Any studies that have been done about treatment options would be helpful.  Also, are there any other published cases of teratoma and astrocytoma?  I guess I am trying to find out if my type of teratoma would portend a better or worse prognosis than other types, especially given how fast mine developed. See answer


  1. El Mesbahi O, Terrier-Lacombe MJ, Rebischung C, Theodore C, Vanel D, Fizazi K. Chemotherapy in patients with teratoma with malignant transformation. European Urology. 2007; 51:1306-1311. http://www.ncbi.nlm.nih.gov/pubmed/17081678. Accessed 9/20/2012.
  2. Athanasiou A, Vanel D, El Mesbahi O, Theodore C, Fizazi K. Non-germ cell tumours arising in germ cell tumours (teratoma with malignant transformation) in men: CT and MR findings. European Journal of Radiology. 2009; 69:230-235. http://www.ncbi.nlm.nih.gov/pubmed/19056194. Accessed 9/20/2012.
  3. Motzer RJ, Amsterdam A, Prieto V, Sheinfeld J, Murty VV, Mazumdar M, Bosl GJ, Chaganti RS, Reuter VE. Teratoma with malignant transformation: diverse malignant histologies arising in men with germ cell tumors. Journal of Urology. 1998; 159:133-138. http://www.ncbi.nlm.nih.gov/pubmed/9400455. Accessed 9/20/2012.