Parathyroid carcinoma

Parathyroid carcinoma is a rare cancer resulting in parathyroid adenoma to carcinoma progression.[1] It forms in tissues of one or more of the parathyroid glands (four pea-sized glands in the neck that make parathyroid hormone (PTH). PTH helps the body maintain normal levels of serum calcium by promoting calcium reabsorption from bone. It is antagonized by the hormone calcitonin, which prompts calcium storage.).

Parathyroid carcinoma
Parathyroid gland anatomy(green marks)
SpecialtyOncology, ENT surgery

It is rare,[2] and much less common than parathyroid adenoma. It can be difficult to excise.[3]

Signs and symptoms

Most patients experience moderate to severe hypercalcemia and high parathyroid hormone levels. A large mass in the neck is often seen, and kidney and bone abnormalities are common.[1]

Risk factors

Parathyroid cancer occurs in midlife at the same rate in men and women.

Conditions that appear to result in an increased risk of parathyroid cancer include multiple endocrine neoplasia type 1,[4] autosomal dominant familial isolated hyperparathyroidism[4] and hyperparathyroidism-jaw tumor syndrome[1] (which also is hereditary).[1] Parathyroid cancer has also been associated with external radiation exposure, but, most reports describe an association between radiation and the more common parathyroid adenoma.[4]

Treatment

Parathyroid carcinoma is sometimes diagnosed during surgery for primary hyperparathyroidism. If the surgeon suspects carcinoma based on severity or invasion of surrounding tissues by a firm parathyroid tumor, aggressive excision is performed, including the thyroid and surrounding tissues as necessary.[1]

Agents such as calcimimetics (for example, cinacalcet) are used to mimic calcium and are able to activate the parathyroid calcium-sensing receptor (making the parathyroid gland "think" we have more calcium than we actually do), therefore lowering the calcium level, in an attempt to decrease the hypercalcemia.

References
  1. Hu MI, Vassilopoulou-Sellin R, Lustig R, Lamont JP. "Thyroid and Parathyroid Cancers" in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) Cancer Management: A Multidisciplinary Approach. 11 ed. 2008.
  2. Lee JE (July 2005). "Predicting the presence of parathyroid carcinoma". Ann. Surg. Oncol. 12 (7): 513–4. doi:10.1245/ASO.2005.03.904. PMID 15952075.
  3. "Endocrine Pathology". Retrieved 2009-05-08.
  4. Parathyroid Cancer Treatment at National Cancer Institute. Last Modified: 03/11/2009.
Classification
External resources

 This article incorporates public domain material from the U.S. National Cancer Institute document: "Dictionary of Cancer Terms".

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