A nationwide study on parathyroid carcinoma

: Ryhanen EM, Leijon H, Metso S, Eloranta E, Korsoff P, Ahtiainen P, Kekalainen P, Tamminen M, Ristamaki R, Knutar O, Loyttyniemi E, Niskanen L, Vaisanen M, Heiskanen I, Valimaki MJ, Laakso M, Haglund C, Arola J, Schalin-Jantti C, Schalin-Jantti C

Publisher: TAYLOR & FRANCIS LTD

: 2017

: Acta Oncologica

: ACTA ONCOLOGICA

: ACTA ONCOL

: 56

: 7

: 991

: 1003

: 13

: 0284-186X

: 1651-226X

DOI: https://doi.org/10.1080/0284186X.2017.1306103

Background: Parathyroid carcinoma (PC) is rare and diagnostically challenging. Reported outcomes are rather poor and the incidence might be increasing.Material and methods: We performed a nationwide study on all cases (n=32) diagnosed in 2000-2011 in Finland, and compared clinical and histopathological characteristics and outcome to atypical parathyroid (APA; n=28) and parathyroid adenomas (PA; n=72). The incidence in years 1955-1999 was compared to that in 2000-2013.Results: Preoperatively, calcium and parathyroid hormone concentrations were higher in PC compared to APA and PA (1.76, 1.56 and 1.44mmol/l, p<.001; and 989, 355 and 160mol/l, p<.001, respectively). Calcium was 1.77mmol/l for all PAs. Hospitalization (44% vs. 22% and 3%, respectively, p=.01), renal (50% vs. 48% vs. 22%, respectively, p=.01) and bone (47% vs. 15% vs. 38%, respectively p=.002) manifestations were more common. PC and APA tumors were larger than PA (p<.001). Histopathological characteristics of PC compared to PA are increased mitotic activity (p=.001), chief cells (p=.003), diffuse growth pattern (p<.001), higher Ki67 (p<.001) and negative parafibromin (p<.001). One PC (1/18) and one APA (1/16) patient had a CDC73 mutation. After 6.7 (2-13.9) years of follow-up, 9.4% of PC had residual, 21% recurrent disease and 12.5% died of disease. Overall mortality did not differ between subgroups (p=.094). Recurrent PC was characterized by vascular invasion, lymph node metastases, high mitotic activity, necrosis and negative parafibromin. Incidence increased from 1.42 (range 0.52-2.14) to 7.14 (range 3.42-10.38)/10.000.000/years; (p<.001).Conclusions: PC associates with severe primary hyperparathyroidism and must be suspected if calcium 1.77mmol/l. The prevalence of CDC73 germline mutations in PC and APA in Finland is 6%. PC has distinct histopathological characteristics and its incidence has increased over the past decades.