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Old 11-10-2011
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Thyroid Congo Red Stain of a Thyroid Mass!

37-year-old man presents with a single, firm mass within the thyroid gland. This patient's father developed a tumor of the thyroid gland when he was 32 years of age. Histologic examination of the mass in this 37-year-old man reveals organoid nests of tumor cells separated by broad bands of stroma, as seen in the photomicrograph. The stroma stains positively with Congo red stain and demonstrates yellow-green birefringence. Which of the following is the most likely diagnosis?

Congo Red Stain of a Thyroid Mass!-thyroid.jpg
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A. Follicular carcinoma
B. Papillary carcinoma
C. Squamous cell carcinoma
D. Medullary carcinoma
E. Anaplastic carcinoma

Last edited by scopusmount; 11-10-2011 at 09:50 AM.
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Old 11-10-2011
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Calcitonin forms amyloid,that's congo positive
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Old 11-11-2011
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EXPLANATION: The development of a thyroid mass in a young person who gives a familial history for a similar lesion should raise high clinical suspicion of the possibility that the mass is a medullary carcinoma of the thyroid (MCT). MCT is a tumor of the parafollicular (C) cells of the thyroid and as such is associated with secretion of calcitonin. The procalcitonin is deposited in the stroma of the tumor and appears as amyloid, which stains positively with Congo red stain. The tumor cells have peripheral nuclei that give them a plasmacytoid appearance when viewed cytologically with fine-needle aspiration (FNA). Electron microscopy reveals membrane-bound dense-core neurosecretory granules in the neoplastic cells. MCT may secrete other substances in addition to calcitonin, such as ACTH, CEA, and serotonin. It is also associated with paraneoplastic syndromes, such as carcinoid syndrome (due to serotonin) and Cushing's syndrome (due to ACTH).
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The above post was thanked by:
Farrukh Munir (11-17-2011), inno (11-12-2011), Netgear (11-23-2015)



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Endocrine-, Micrographs-, Pathology-, Step-1-Questions

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