The ratio of PTH as measured by third and second generation assays as a marker for parathyroid carcinoma

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Clinical and genetic characterization of FIPA (familial isolated pituitary adenomas)

peer reviewedPituitary adenomas are common brain tumours at autopsy and radiological series of unselected population. Historically, few epidemiologic data regarding the prevalence of clinically apparent pituitary adenomas have been available. Recently, a cross-sectional study conducted in Liege, Belgium, noted that clinically-apparent pituitary adenomas occurred with a prevalence of 1:1064 inhabitants, which is 3.5-5 times the previously reported prevalence. Pituitary adenomas occur predominantly as sporadic tumors, but also in a familial setting or associated to some familial/isolated tumoral syndromes. The recent characterization of the novel clinical entity FIPA (Familial Isolated Pituitary Adenomas) increased the prevalence of familial pituitary adenomas which account now for about 5% of pituitary tumors. Distinct genetic mechanisms are continuously identified and increase our understanding of the complex clinical presentation and sometimes unpredictable evolution of pituitary adenomas.Les adénomes hypophysaires représentent une pathologie fréquente parmi les tumeurs cérébrales. Une étude liégeoise récente a montré une prévalence des adénomes hypophysaires cliniquement actifs de 1: 1.064 habitants, nettement supérieure aux données antérieures. Tant dans les séries cliniques qu'autopsiques, les microadénomes à prolactine sont les adénomes prédominants. Les adénomes hypophysaires sont le plus souvent de présentation sporadique, mais des adénomes familiaux dans des formes isolées ou syndromiques sont également décrits. Les adénomes hypophysaires familiaux représentent environ 5% des adénomes hypophysaires et leur caractérisation clinique et génétique a été récemment enrichie par la description de la nouvelle entité FIPA (Familial Isolated Pituitary Adenomas) et des mutations du gène AIP (Aryl hydrocarbon receptor-Interacting Protein). Bien que d'évolution habituellement bénigne, les adénomes hypophysaires sont caractérisés par une grande diversité clinique et génétique qui réclame des moyens diagnostiques et thérapeutiques spécifiques

The Ratio of Parathyroid Hormone as Measured by Third- and Second-Generation Assays as a Marker for Parathyroid Carcinoma.

Background: Parathyroid carcinoma (PCa) is a rare disease that can be difficult to differentiate initially from severe benign parathyroid adenoma. PCa oversecrete the amino form of PTH, which is recognized by third-generation but not by second-generation PTH immunoassays. In normal individuals, the third-generation to second-generation PTH ratio should be less than 1. Objective: Our objective was to study the utility of the third-generation to second-generation PTH ratio as a means of distinguishing PCa patients (n = 24) from control groups with and without disorders of calcium secretion, including patients on renal hemodialysis (n = 74), postrenal transplantation (n = 60), and primary hyperparathyroidism (PHP; n = 30). Setting and Design: We conducted a retrospective, laboratory-based study at tertiary referral academic centers. Results: The mean third-generation to second-generation ratio was 0.58 ± 0.10 in the dialysis patients, 0.54 ± 0.10 in the renal transplant group, 0.54 ± 0.12 in the elderly healthy patients, and 0.68 ± 0.11 in the PHP group. All 245 of these patients presented a PTH third-generation to second-generation ratio of less than 1. In contrast, we observed an inverted third-generation to second-generation PTH ratio of more than one in 20 PCa patients, whereas only four PCa patients had a normal ratio of less than 1. Conclusions: An inverted third-generation to second-generation PTH ratio occurred in the majority of patients with advanced PCa and was absent in all 245 relevant controls. A third-generation to second-generation PTH ratio higher than 1 had a sensitivity of 83.3% and a specificity of 100% among PHP patients as a marker for PCa. This ratio may be useful to identify patients with PCa earlier and to detect patients either at risk of developing PCa or those in whom recurrence is taking place