Relationship between the dimension of parathyroid glands estimated by ultrasonography and the hyperplastic pattern in patients with renal hyperparathyroidism

In renal hyperparathyroidism (HPT), the parathyroid glands initially proliferate diffusely and polyclonally, and are then transformed to monoclonal nodular hyperplasia with aggressive growth potential. In this study we evaluated the relationship between the maximal dimension of parathyroid glands estimated by ultrasonography (US) and the hyperplastic pattern of parathyroid glands in patients with renal HPT. Between October 1999 and December 2006, 141 patients who underwent total parathyroidectomy (PTx) with forearm autograft in our department were enrolled in this study. In these patients 308 parathyroid glands were detected by US before PTx. The largest dimension of the gland estimated preoperatively by US was correlated closely with its measurement at surgery (R2 was 0.31, P < 0.001). The maximal dimension of diffuse hyperplastic glands was significantly smaller than that of the glands with nodular hyperplastic glands (P < 0.001). There was a strong correlation between the pattern of parathyroid hyperplasia and the glandular diameter when we defined 8 mm as the maximal diameter estimated by US as a cut-off value. As a result of receiver operating characteristic analyses, using these criteria the US technique could predict nodular hyperplasia with a high sensitivity (78.9%) and specificity (78.7%). Parathyroid glands that are enlarged by more than 8 mm in the largest dimension estimated by US may represent glands with nodular hyperplasia.