Most common primary malignant tumour of orbit is: September 2011, March 2013 (b, d)
Correct Answer: Rhabdomyosarcoma
Description: Ans. B: Rhabdomyosarcoma Malignant tumours of the orbit are usually sarcomata Rhabdomyosarcomata are extremely malignant tumours Rhabdomyosarcoma It is a cancer, specifically a sarcoma (cancer of connective tissues), in which the cancer cells are thought to arise from skeletal muscle progenitors. It can olso be found attached to muscle tissue, wrapped around intestines, or in any anatomic location. Most ouyir in areas naturally lacking in skeletal muscle, such as the head, neck, and genitourinary tract. Presentation Its two most common forms are embryonal rhabdomyosarcoma and alveolar rhabdomyosarcoma. In the former, which is more common in younger children, the cancer cells resemble those of a typical 6-to-8-week embryo. In the latter, which is more common in older children and teenagers, they resemble those of a typical 10-to-12-week embryo. Epidemiology It is most common in children ages one to five, and is also found in teens aged 15 to 19, although this is more rare. Rhabdomyosarcoma is the most common soft tissue sarcoma in children. Soft tissue sarcomas make up about 3% of childhood cancers. Diagnosis Diagnosis of rhabdomyosarcoma depends on recognition of differentiation toward skeletal muscle cells. The proteins myoD1 and myogenin are transcription factor proteins normally found in developing skeletal muscle cells which disappears after the muscle matures and becomes innervated by a nerve. Thus, myoD1 and myogenin are not usually found in normal skeletal muscle and serve as a useful immunohistochemical marker of rhabdomyosarcoma. Treatment Treatment for rhabdomyosarcoma consists of chemotherapy, radiation therapy and sometimes surgery. Surgery to remove the tumor may be difficult or impossible depending on the location of the tumor.
Category:
Ophthalmology
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