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Chapter 16: Pathology of the Endocrine System

Which of the following is true about thyroid cancer?

A. Tumors are most commonly diagnosed in older males.

B. Most spread by hematogenous metastases.

C. The most common subtype is follicular carcinoma.

D. Most have fairly indolent biologic behavior.

E. Most are derived from calcitonin-secreting cells of the thyroid.

Answer: D

Explanation: Thyroid cancer is most commonly diagnosed in young to middle aged females (and most are papillary carcinoma), and in this age group most have indolent biologic behavior. While much less common, tumors diagnosed in older patients, particularly older males, have more aggressive biologic behavior. The most common subtype by far of thyroid cancer is papillary carcinoma, and follicular carcinoma is (a distant) second. When metastatic, most carcinomas (particularly papillary carcinoma) spread by lymphatic invasion to local lymph nodes. Most thyroid cancers arise from follicular cells of the thyroid. The exception is medullary carcinoma, which is derived from the C cells (calcitonin-secreting cells) of the thyroid.

What is the most common cause of gluticorticoid excess (Cushing’s syndrome)?

A. Adrenal cortical hyperplasia

B. Adrenal cortical adenoma

C. Adrenal cortical carcinoma

D. Pheochromocytoma

E. Pituitary adenoma

Answer: E

Explanation: Most cases (70-80%) of Cushing’s syndrome are due to an ACTH secreting pituitary adenoma. This condition has the confusing name of “Cushing’s disease.” The ACTH secreting pituitary tumor drives the adrenal gland to develop bilateral adrenal cortical hyperplasia, the changes in the adrenal are secondary and not primary. So called “adrenal Cushing’s” is due to a primary neoplasm in the adrenal, either adrenal cortical adenoma or adrenal cortical carcinoma. But this is a much less common cause of Cushing’s syndrome than a pituitary adenoma (only about 8% of Cushing’s syndrome cases are caused by a primary adrenal neoplasm). Pheochromocytoma is a neoplasm of the adrenal medulla or neural crest cells outside of the adrenal gland (sympathetic or parasympathetic tissue, where it can also be termed paraganglioma or extra-adrenal pheochromocytoma), and these do not produce gluticorticoids but rather metanephrines when functional.

A 36-year-old woman presents with fatigue, unintended weight loss and orthostatic hypotension. Laboratory workup demonstrates FT4 and TSH within normal limits, elevated potassium (5.6 mmol/L), elevated FSH, normal prolactin and growth hormone, and low cortisol. Gross assessment is notable of diffuse enlargement of the thyroid and thinning or absent hair. Results of ...

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