Parathyroid Carcinoma Encountered After Minimally Invasive Focused Parathyroidectomy may not Require Further Radical Surgery
- 143 Downloads
Parathyroid carcinoma accounts for <1% of tumors in primary hyperparathyroidism (PHPT). Distinguishing parathyroid malignancy from benign disease is difficult both before and after initial surgery. Despite the improved specificity of a malignant diagnosis with immunohistochemistry for parafibromin and PGP9.5, proven metastatic behavior remains the gold standard of diagnosis. Minimally invasive focused parathyroidectomy (MIP) is widely performed in patients with PHPT and positive localization studies; thus, it is inevitable that some parathyroid caricnomas will be encountered at MIP. We present our experience of this rare entity.
The present study represents a surgical case series of patients with parathyroid carcinoma encountered after MIP. The clinicopathological features of benign and malignant parathyroid tumors were compared. Multiple regression analysis was undertaken to compare indicators of malignancy.
Between May 1999 and April 2010, a total of 1,292 patients underwent MIP at the University of Sydney Endocrine Surgical Unit, and a histopathological diagnosis of parathyroid carcinoma was made in seven patients (0.5%). Staining for parafibromin and/or PGP9.5 was abnormal in five carcinomas (71%). Despite subsequent unilateral thyroid lobectomy and lymphadenectomy in six patients, no further malignancy was identified in any specimens. Compared to controls, preoperative calcium (p = 0.04) and parathyroid hormone (p = 0.01) were significantly higher in patients with malignancy. The positive predictive value of these parameters for carcinoma was 56 and 75%, respectively.
In patients diagnosed with parathyroid carcinoma after MIP where preoperative imaging had already demonstrated localized disease, revision en bloc surgery did not reveal any residual disease. The benefits of further radical surgery for parathyroid carcinoma after MIP remain controversial.
KeywordsPrimary Hyperparathyroidism Cinacalcet Parathyroid Carcinoma Central Neck Dissection Bilateral Neck Exploration
Dr. C. J. O’Neill is supported by a grant from the New South Wales Cancer Institute. Stan B. Sidhu is a New South Wales Cancer Institute Fellow. An earlier form of this article was presented as a poster presentation at the Society of Surgical Oncology, St. Louis, MO, March 2010.
- 4.Bondeson L, Grimelius L, Delellis RA (2004) Parathyroid carcinoma. In: Delellis RA, Lloyd RV, Heitz PU (eds) World Health Organisation classification of tumours, pathology and genetics: tumour of endocrine organs. IARC Press, Lyon, p 124Google Scholar
- 7.Howell VM, Haven CJ, Kahnoski K et al (2003) HRPT2 mutations are associated with malignancy in sporadic parathyroid tumours. J Med Genet 40:657 [Erratum appears in J Med Genet 41(1):20, 2004]Google Scholar
- 23.Iihara M, Okamoto T, Suzuki R et al (2007) Functional parathyroid carcinoma: long-term treatment outcome and risk factor analysis. Surgery 142:936 [Erratum appears in Surgery 143:302, 2008]Google Scholar
- 27.Hundahl SA, Fleming ID, Fremgen AM et al (1999) Two hundred eighty-six cases of parathyroid carcinoma treated in the U.S. between 1985–1995: a National Cancer Data Base Report. The American College of Surgeons Commission on Cancer and the American Cancer Society. Cancer 86:538CrossRefPubMedGoogle Scholar
- 31.Ishida T, Yokoe T, Izuo M (1991) Nationwide surgery of parathyroid operations in Japan (1980–1989). Endocr Surg (Tokyo) 8:37Google Scholar