Tominaga Y, Tanaka Y, Sato K, Nagasaka T, Takagi H
Department of Transplant Surgery, Nagoya Second Red Cross Hospital, Japan.
Semin Surg Oncol. 1997 Mar-Apr;13(2):78-86. doi: 10.1002/(sici)1098-2388(199703/04)13:2<78::aid-ssu3>3.0.co;2-z.
Morphological changes in the parathyroid glands evidently occur early during renal failure. Histopathological investigations have suggested that parathyroid cells initially increase diffusely with a normal lobular structure (diffuse hyperplasia). The parathyroid glands then become hyperplastic with some nodules (nodular hyperplasia). Cells in nodules grow monoclonally and proliferate aggressively, possibly induced by some kind of genetic abnormality. Pathophysiologically, in cells consisting of hyperplastic nodules, suppression of parathyroid hormone (PTH) secretion under the influence of excess extracellular calcium is more deranged, possibly due to a reduction of calcium-sensing receptors. Vitamin D receptor density decreases more severely in these cells, possibly causing abnormal PTH synthesis, PTH secretion, and even parathyroid cell proliferation. According to histopathological and pathophysiological findings, patients with nodular hyperplasia during renal hyperparathyroidism may be refractory to medical treatments, including calcitriol pulse therapy, and parathyroidectomy will become necessary. There is a relationship between the pattern of parathyroid hyperplasia and glandular weight in which glands weighing more than 500 mg may be pathognomonic of nodular hyperplasia. Glandular volume, estimated by ultrasonography, is one of several important criteria indicating parathyroidectomy. In order to prevent a recurrence of hyperparathyroidism, all nodular hyperplastic tissue should be extirpated.
甲状旁腺的形态学改变显然在肾衰竭早期就已出现。组织病理学研究表明，甲状旁腺细胞最初呈弥漫性增加，小叶结构正常（弥漫性增生）。随后甲状旁腺出现增生并伴有一些结节（结节性增生）。结节内的细胞呈单克隆生长且增殖活跃，可能是由某种基因异常所诱导。从病理生理学角度来看，在由增生性结节组成的细胞中，细胞外钙过量时甲状旁腺激素（PTH）分泌的抑制作用更加紊乱，这可能是由于钙敏感受体减少所致。这些细胞中维生素D受体密度下降更为严重，可能导致PTH合成异常、PTH分泌异常，甚至甲状旁腺细胞增殖。根据组织病理学和病理生理学研究结果，肾性甲状旁腺功能亢进症患者若出现结节性增生，可能对包括骨化三醇冲击疗法在内的药物治疗无效，甲状旁腺切除术将成为必要手段。甲状旁腺增生的模式与腺体重量之间存在关联，腺体重量超过500mg可能是结节性增生的特征性表现。通过超声检查估计的腺体体积是表明需要进行甲状旁腺切除术的几个重要标准之一。为防止甲状旁腺功能亢进症复发，应切除所有结节性增生组织。
