title: Reversed whole PTH/intact PTH ratio as an indicator of marked parathyroid enlargement: five case studies and a literature review.
abstract: Parathyroid hormone (PTH) levels detected by intact PTH assays are generally higher than those detected by the whole PTH assay because the latter does not detect non-(1-84) PTH fragments, mainly PTH (7-84). Rare exceptions to this rule have been reported in patients with severe primary or secondary hyperparathyroidism and parathyroid carcinoma. Overproduction of an N-form of PTH other than PTH (1-84) has been observed in the sera of these patients. We report five additional cases with the reversed whole PTH/intact PTH ratio associated with severe hyperparathyroidism in haemodialysis patients. Three patients demonstrated enlargement of a single hypervascular gland, whereas the other two had undergone surgical parathyroidectomy and later showed recurrent hyperparathyroidism due to progressive autograft hyperplasia. In the case of a single enlarged gland, the pathological pattern and heterogeneous expression of parathyroid adenomatosis 1/cyclin D1 suggested it to be a single nodule of uraemic hyperparathyroidism rather than sporadic primary adenoma. These cases suggested that the reversed whole PTH/intact PTH ratio could be an indicator of marked parathyroid enlargement. Further studies are required to elucidate the clinical significance of the reversed whole PTH/intact PTH ratio in haemodialysis patients.
authors.affiliation: Division of Nephrology and Kidney Center , Kobe University School of Medicine , Kobe 650-0017.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Komaba
authors.affiliation: Division of Nephrology and Kidney Center , Kobe University School of Medicine , Kobe 650-0017.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Motomachi HD Clinic, Kobe, 650-0012.
authors.forename: Jeongsoo
authors.initials: J
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine , Tokai University School of Medicine , Isehara, 259-1193.
authors.forename: Reika
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Internal Medicine , Tokai University School of Medicine , Isehara, 259-1193.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kakuta
authors.affiliation: Department of Transplant and Endocrine Surgery , Nagoya Second Red Cross Hospital , Nagoya, 466-8650 , Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tominaga
authors.affiliation: Division of Nephrology and Kidney Center , Kobe University School of Medicine , Kobe 650-0017.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukagawa
keywords: N-PTH; intact PTH; secondary hyperparathyroidism; single nodule; whole PTH