Parathyroid cancer pathophysiology: Difference between revisions
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==Genetics== | ==Genetics== | ||
* HRPT2/CDC73 gene is involved in the pathogenesis of parathyroid cancer. | * HRPT2/CDC73 gene is involved in the pathogenesis of parathyroid cancer. | ||
==Associated Conditions== | ==Associated Conditions== | ||
* Multiple endocrine neoplasia 1 | * Multiple endocrine neoplasia 1 | ||
Revision as of 17:40, 23 December 2015
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Parathyroid cancer Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Parathyroid cancer pathophysiology On the Web |
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American Roentgen Ray Society Images of Parathyroid cancer pathophysiology |
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Risk calculators and risk factors for Parathyroid cancer pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]
Overview
Pathogenesis
- Parathyroid cancer typically runs an indolent course because the tumor has a rather low malignant potential.
- At initial presentation, very few patients with parathyroid carcinoma have metastases either to regional lymph nodes (<5%) or distant sites (<2%).
- A higher proportion of parathyroid cancers locally invade the thyroid gland, overlying strap muscles, recurrent laryngeal nerve, trachea, or esophagus. Parathyroid carcinoma tends to be localized in the inferior parathyroid glands; one series reported that the primary tumor originating in the inferior parathyroid glands was found in 15 of 19 cases involving local invasion.
- Approximately 40% to 60% of patients experience a postsurgical recurrence, typically in the range of 2 to 5 years after the initial resection. In most cases, hypercalcemia precedes physical evidence of recurrent disease.
- The location of recurrence is typically regional, either in the tissues of the neck or in cervical lymph nodes, and accounts for approximately two thirds of recurrent cases. Distant metastases were reported to occur in 25% of patients, primarily in the lungs but also in the bone and liver. Serum PTH levels may be 3 to 10 times above the upper limit of normal and hence cause nephrolithiasis or nephrocalcinosis.
Genetics
- HRPT2/CDC73 gene is involved in the pathogenesis of parathyroid cancer.
Associated Conditions
- Multiple endocrine neoplasia 1
- Autosomal dominant familial isolated hyperparathyroidism
Gross Pathology
- Operatively, parathyroid cancers may be distinguished from adenomas by their firm, stony-hard consistency and lobulation; adenomas tend to be soft, round, or oval in shape, and of a reddish-brown color.
- In most series, the median maximal diameter of parathyroid carcinoma is between 3.0 cm and 3.5 cm compared with approximately 1.5 cm for benign adenomas.
- In approximately 50% of the patients, the malignant tumor is surrounded by a dense, fibrous, grayish-white capsule that infiltrates adjacent tissues. The clinical features of parathyroid carcinoma are caused primarily by the effects of excessive secretion of parathormone (PTH) by the tumor rather than by the infiltration of vital organs by tumor cells.
Microscopic Pathology
- Histopathologically, as with other endocrine neoplasms, the distinction between benign and malignant parathyroid tumors is difficult to make.
- Features such as dense fibrous trabeculae, trabecular growth patterns, mitoses, and capsular invasions, which have been classically associated with carcinomas, have also been found in parathyroid adenomas.
- Capsular and vascular invasion appears to correlate best with tumor recurrence.