Inflammatory diseases of the parathyroid gland

Aims: Inflammatory disorders of the parathyroid gland are very rare as compared with those of other endocrine organs. The aim of this study was to provide the first systematic review of this condition. Methods and results: A 42-year-old patient underwent surgery for recurrent secondary hyperparathyroidism. Histology showed hyperplastic parathyroiditis defined by a mixed inflammatory infiltrate with active germinal centres. Molecular markers revealed significant upregulation of CD68 in an ischaemic background (hypoxiainducible factor 1 upregulation) with mitochondrial reaction (malate dehydrogenase 2 upregulation) and hyperparathyroidism (carbonic anhydrase 4 upregulation). Our case demonstrates true intraparathyroid inflammation with terminal B-cell differentiation. We searched PubMed, ISI Thompson and Google Scholar up to January 2011, using the terms ` parathyroiditis', inflammation of parathyroid gland', 'lymphocytic infiltrate', 'tuberculosis of the parathyroid', 'sarcoidosis', and 'graulomatous inflammation'. Three autopsy series, 27 articles and 96 case reports with inflammatory parathyroid disorders were identified. Autopsy series showed lymphocytic infiltrates in up to 16% of all cases. The entire material reported lymphocytic infiltrates (n = 69), parathyroiditis with germinal centres (n = 15), sarcoidosis (n = 6), tuberculosis (n = 4), and other granulomatous diseases (n = 2). Conclusions: Distinct inflammatory and granulomatous processes in the parathyroid gland are rare. Scanty lymphocytic infiltrates are common, and occur in generalized inflammatory conditions or venous congestion. We note the surprising absence of an association between histological proof of parathyroiditis and hypoparathyroidism.