myxoma

A benign neoplasm derived from connective tissue, consisting chiefly of polyhedral and stellate cells that are loosely embedded in a soft mucoid matrix, thereby resembling primitive mesenchymal tissue; occurs frequently intramuscularly (where it may be mistaken for a sarcoma), also in the jaw bones, and encysted in the skin (focal mucinosis and dorsal wrist ganglion). [myxo- + G. -oma, tumor]

- atrial m. a primary cardiac neoplasm arising most commonly in the left atrium as a soft polypoid mass attached by a stalk to the atrial septum; it may resemble an organized mural thrombus, and the symptoms may include cardiac murmurs, which change with alteration of body position and signs of mitral stenosis or insufficiency, with continuous danger of embolism by fragments of the tumor or its entire mass.

- m. enchondromatosum SYN: myxochondroma.

- m. fibrosum SYN: myxofibroma.

- m. lipomatosum SYN: myxolipoma.

- odontogenic m. a benign, expansile, multilocular radiolucent neoplasm of the jaws consisting of myxomatous fibrous connective tissue; presumably derived from the mesenchymal components of the odontogenic apparatus.

- m. sarcomatosum SYN: myxosarcoma.

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myx·o·ma mik-'sō-mə n, pl -mas also -ma·ta -mət-ə a soft tumor made up of gelatinous connective tissue resembling that found in the umbilical cord

myx·o·ma·tous -mət-əs adj

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n.

a benign gelatinous tumour of connective tissue. Atrial myxoma is a tumour of the heart, usually of the left side, arising from the septum dividing the two upper chambers. Symptoms may include fever, lassitude, joint pains, and sudden loss of consciousness due to obstruction of the bloodflow. The tumour may be wrongly diagnosed as stenosis of the mitral valve as it can produce a similar murmur. Treatment requires surgical removal.

• myxomatous adj.

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myx·o·ma (mik-soґmə) pl. myxomas, myxoґmata [myx- + -oma] a benign tumor composed of primitive connective tissue cells and stroma resembling mesenchyme. Called also colloid tumor, gelatinous tumor, and mucous tumor. myxomatous adj