Dictionary > Thymoma

Thymoma

Thymoma
(Science: oncology, tumour) A tumour of thymic origin.
thymoma is a cancerous condition of the Thyamus gland. Located at the
top of the heart, the thyamus gland contributes to the function of the
immune system prior to puberty. At puberty, other organs take over the
immune functions and the thyamus begins to be re-absorbed by the body,
usually turning into fatty Tissue. In rare cases, the tissue of the
thyamus becomes cancerous and a tumor begins to grow. These tumors are
usually epithelial in nature although there are some variations
(for more information see the WHO thymoma typing standards).
thymoma is different from other cancer types which is illistrated by it’s
behavior.
1. Thymoma cells do not change characteristics over the course of the
disease.
2. Thymoma does not spread through the lymph system like other cancers and
therefore remains localized to the chest cavity.
3. Thymoma is staged differently than most other cancers using a scale called
the Masoaka scale which is based on the amount of matastasis within the
chest cavity.
stage 1: Only one tumor located at the thyamus exists and it is
fully encapsulated or calcified.
stage 2: The tumor is no longer encapsulated, but there are no
signs of matastasis.
stage 3: tumor has begun to matastasize to other local organs and
structures like the outer lining of the lungs, aorta,
heart, or esophagus.
stage 4a: thymoma cells have matastasized to more remote structures
in the chest cavity which may include but not be limited
to the hilum, paracardium, diaphram.
stage 4b: Tumors have spread throughout the chest cavity and have
become invasive to the other organs.
Preferred treatment is surgical resection and is the most successful
in stages 1 and 2. resection is still usually possible in stage 3,
however the risk of recurrance is significantly higher. resection of
stage 4 is usually referred to as “debulking” due to the fact that
the odds of complete resection of all cancerous tissue is practically
impossible without removing large sections of other organs which
increases morbidity without decreasing the recurrance statistics.
treatment of stages 1-3 usually includes chemotherapy both neojunctive
and adjunctive. Preferred substances are cisplatin and Etopiside given
in combination. Other substances maybe substituted, but will be from
the same family of chemo drugs. Both subcatagories of stage 4 will be
treated almost exclusively with a chemotherapy regimen unless the
oncologist and surgeon decide that debulking will either improve the
quality of the patients life or significantly increase the patients
longevity.
radiation treatment is an option, however due to the tumor’s proximity
to the heart and lungs, it may be considered too risky for more advanced
cases. radiation will usually be given both neojuntively and
adjunctively to resections of stage 1 and 2 tumors. application to
stage 3 is usually at the radiology oncologist’s discretion.
thymoma is usually grouped with another condition called Thymic
carcinoma, mostly due to the fact that they are both cancerous
conditions of the thyamus. however, they are distinctly different
diseases with different cellular characteristics and different behaviors.
thymoma and thyamic carcinoma as a group are relatively rare. At the
time of this writing they account for less than 2% of all cancers
reported in the united states on an annual basis. As of this time
there are no known causes of thymoma or Thyamic carcinoma. Links to
any environmental, or hereditary characteristics have not been found
and there are no known carcinogens that cause it’s formation.


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