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| Did you find this easy | |||
| Yes |
new_n_lost |
1 | 33% |
| NO |
brainstem, Ferritin |
2 | 67% |
| 3 votes | |||
| Author | 7 Posts | |||||||||||||||||||||||||||||||||||||||||||||||||
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NNL
Awaitin The Unexpected  Topics: 779 Posts: 6613 |
A 51-year-old woman presents with problems seeing and drooping eyelids. She had been diagnosed 5 years prior as having lupus. A chest x-ray reveals a mass in the anterior mediastinum, which is confirmed by a CT scan. Surgical exploration finds a well-encapsulated tumor. No evidence of invasion is seen. The mass is resected, and histologic sections reveal scattered lymphocytes within a diffuse proliferation of spindle-shaped cells. Which of the following is the cell of origin of this tumor? a. Epithelial cells of the thymus b. Fibroblasts of the mediastinal mesenchyme c. Follicular cells of ectopic thyroid tissue d. Immature T lymphocytes of the thymus e. Mesothelial cells of the mediastinal mesothelium
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loto
| Forum Senior Topics: 4 Posts: 133
A thymoma
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SILVER
| DoWhatYouGotToDo!  Topics: 56 Posts: 1289
A
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keepgoing
| .....  Topics: 109 Posts: 1865
a
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brainstem
| Forum Junior  Topics: 30 Posts: 1531
A
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NNL
| Awaitin The Unexpected Topics: 779 Posts: 6613
loto wrote: A thymoma 
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NNL
| Awaitin The Unexpected Topics: 779 Posts: 6613
The answer is a. Thymomas are tumors arising from thymic epithelial cells and are among the most common mediastinal neoplasms, especially in the anterosuperior mediastinum. Histologic sections reveal a proliferation of spindle-shaped cells. There is a scanty or rich lymphocytic infiltrate of T cells, which are not neoplastic, although their size and prominent nucleoli may cause histologic confusion with lymphoma. About 90% of thymomas are benign and occur at a mean age of 50 years. They are very rare in children. They may be asymptomatic or may cause pressure effects of dysphagia, dyspnea, or vena cava compression. Associated systemic disorders include myasthenia gravis, hematologic cytopenias, collagen vascular disease (lupus), and hypogammaglobulinemia. Malignant thymomas show infiltration and capsular invasion plus pleural implants or distant metastasis. In contrast, the other type of cell found in the thymus, T lymphocytes; give rise to T-cell lymphoblastic lymphomas. Finally, recall that fibroblasts give rise to fibromas or fibrosarcomas, and mesothelial cells give rise to benign or malignant mesotheliomas.
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