Practice questions answers Pathology of parathyroid gland/MEN

Practice questions answers

Pathology of parathyroid gland/MEN

1. C. The causes of hypercalcemia are variable. The first laboratory test for patient with hypercalcemia, as recommended by American Academy of Family Physicians, is intact parathyroid hormone (PTH). Bone marrow biopsy and immunofixation are for multiple myeloma, plasmacytoma and other lymphoid neoplasms. These disorders commonly have abnormal urine immunoglobulins. MRI breast examination may be used to detect recurrent breast cancers. Parathyroid hormone related peptide may be produce by solid tumors, such as squamous cell carcinoma of lung.

2. B. Elevated PTH in a patient with hypercalcemia is either primary or tertiary hyperparathyroidism. However, tertiary hyperparathyroidism is defined as autonomous hypersecretion of parathyroid hormone in a patient with long standing secondary hyperparathyroidism. This patient does not have any secondary hyperparathyroidism associated history, such as renal failure, etc. Tumor associated bone lysis and subsequent hypercalcemia usually has suppressed PTH. Pseudohypoparathyroidism may have elevated PTH, but in a background of hypocalcemia.

3. E. Primary hyperparathyroidism can be caused by either parathyroid adenoma or hyperplasia. Sestamibi scan is recommended prior to surgery, since it will detect parathyroid adenoma, but NOT hyperplasia. Also see discussion in question 1.

4. D. See discussion is question 3.

5. D. Osteitis fibrosa cystica (brown tumor) is caused by over activation of osteoclasts by PTH, usually starting from of hand and facial bones. They are more commonly seen in primary hyperparathyroidism. Giant cell tumor of bone is more commonly seen in knees, and has sheets of multinucleated giant cells. Granulomatous osteomyelitis has background inflammation. Metastatic breast cancer has atypical epithelial cells. Osteosarcoma is more commonly seen in metaphysis of long bones, especially around knee. It has atypical cells with bone production.

6. D. Parathyroid hyperplasia is characterized by diffuse parathyroid cell proliferation without compressed normal parathyroid tissue. Scattered adipose cells are more commonly seen in hyperplasia, but NOT parathyroid adenoma. In addition, sestamibi scan is sensitive for parathyroid adenoma, but NOT hyperplasia. Chronic renal disease may cause secondary hyperparathyroidism, due to hypocalcemia and phosphorus retention. Parathyroid carcinoma has features of invasion.

7. D. See discussion in question 1. This is an asymptomatic patient with pathological fracture and incidentally detected hypercalcemia.

8. A. Parathyroid gland release PTH in response to hypocalcemia. Neither blood glucose levels nor urine protein influence PTH release. This patient has proteinuria due to diabetic nephropathy. Parathyroid adenoma and carcinoma usually have hypercalcemia.

9. E. One of the pathophysiologic process in renal failure is retention of phosphorus, which causes elevated FGF23 and subsequent suppression of 1,25 (OH)₂D. These effects cause reduced renal reabsorption of calcium, hypocalcemia and stimulate PTH release, as seen in secondary hyperparathyroidism. Hypoparathyroidism has low PTH. Pseudohypoparathyroidism have elevated PTH, hypocalcemia, with childhood onset.

10. D. Secondary hyperparathyroidism is caused by hypocalcemia and phosphorus retention, such as those patients with renal failure. Primary and tertiary hyperparathyroidism has elevated PTH and hypercalcemia. Hypoparathyroidism has low PTH. Pseudohypoparathyroidism have elevated PTH, hypocalcemia, with childhood onset.

11. E. See discussion in questions 2 and 10.

12. C. Parathyroid tumor with invasion is parathyroid carcinoma. Papillary thyroid carcinoma, including follicular variant, is diagnosed based on typical nuclear features, such as enlarged nuclei, washed out chromatin, nuclear grooves or inclusion. Parathyroid adenoma is characterized by nodule growth of parathyroid cells without adipose tissue nor invasion. Parathyroid hyperplasia is characterized by diffuse parathyroid cell proliferation without compressed normal parathyroid tissue. Scattered adipose cells are more commonly seen in hyperplasia, but NOT parathyroid adenoma. Medullary thyroid carcinoma has eccentric nuclei, punctuate chromatin, and amyloid deposit.

13. A. Hypocalcemia and low PTH are seen in hypoparathyroidism. All hyperparathyroidism has elevated PTH. Pseudohypoparathyroidism have elevated PTH, hypocalcemia, with childhood onset.

14. C. See discussion is questions 2 and 13.

15. A. Pancreas tumor with multiple ulcers is suggestive of Zollinger-Ellison Syndrome, a tumor produce gastrin. This patient has a history of prolactinoma. He currently has signs of parathyroid hyperplasia/adenoma, in addition to features of gastrinoma. These findings are highly suggestive of multiple endocrine neoplasia 1. Helicobacter infection is a common cause of peptic ulcer, but usually do not have multiple ulcers. Pseudohypoparathyroidism have elevated PTH, hypocalcemia, with childhood onset. Secondary hyperparathyroidism is caused by hypocalcemia and phosphorus retention, such as those patients with renal failure. Tertiary hyperparathyroidism is defined as autonomous hypersecretion of parathyroid hormone in a patient with long standing secondary hyperparathyroidism.

16. B. Multiple endocrine neoplasia 1 is characterized by combination of pituitary prolactinoma, parathyroid hyperplasia/adenoma, and islet tumor, such as Zollinger-Ellison Syndrome. Metastatic parathyroid carcinoma does not elevate gastrin. Multiple endocrine neoplasia 2 is characterized by medullary thyroid carcinoma, pheochromocytoma, with or without parathyroid manifestations. Parathyroid hyperplasia may be part of the condition, but not the whole disorder with multiple tumors of endocrine organs. Pseudohypoparathyroidism have elevated PTH, hypocalcemia, with childhood onset.

17. A. Menin mutation is seen in multiple endocrine neoplasia 1. NF1 mutation is seen in neurofibromatosis 1. PAX8 mutation can be seen in various tumors, including follicular carcinoma of thyroid. PTEN mutation can be seen in various conditions, including follicular carcinoma of thyroid, endometriosis, endometrioid endometrial adenocarcinoma. RET mutation can be seen in multiple endocrine neoplasia 2, Hirschsprung disease, non-familial medullary thyroid carcinoma, and papillary thyroid carcinoma.

18. B. Thyroid tumor producing calcitonin is medullary thyroid carcinoma. Follicular adenoma of thyroid is composed of packed small follicles. Papillary thyroid carcinoma has classic nuclear features. Both are positive for thyroglobulin and negative for calcitonin. Parathyroid carcinoma usually express PTH. Plasmacytoma is negative for calcitonin.

19. E. See discussion in question 17.

20. C. This patient has a history of parathyroid hyperplasia, and currently presents with medullary thyroid carcinoma. These features are highly suggestive of multiple endocrine neoplasia 2A, although pheochromocytoma is more commonly seen. Papillary thyroid carcinoma has classic nuclear features. Multiple endocrine neoplasia 1 is characterized by combination of pituitary prolactinoma, parathyroid hyperplasia/adenoma, and islet tumor, such as Zollinger-Ellison Syndrome. Multiple myeloma has multifocal lytic bone lesions, but less likely presents with thyroid mass. Plasma cell leukemia is a variant of multiple myeloma, characterized by >20% clonal plasma cells in circulation.

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