A retrospective review of the role of B-mode and color Doppler ultrasonography in the investigation of primary hyperparathyroidism: Features that differentiate benign from malignant lesions.

PURPOSE: To identify the variant features encountered in parathyroid abnormalities and document those suggesting malignant change. MATERIALS AND METHODS: Data were collected from a cohort of patients who underwent investigation for primary hyperparathyroidism over a 10-year period. Ultrasonographic features: shape, presence of calcification, cystic changes, heterogeneous echogenicity, vascularity, capsular thickening, local invasion, and vascularity were reviewed retrospectively and were used to correlate with final histological findings. RESULTS: One hundred forty-seven patients with histology and concurrent ultrasonographic scans were reviewed, and divided into benign parathyroid lesions (nodular hyperplasia (n = 44), adenoma (n = 93)) and parathyroid carcinoma (n = 10). Parathyroid carcinomas were significantly larger than benign parathyroid lesions (P = 0.030). Benign parathyroid lesions showed variant sonographic features: irregular shape (16.8%), heterogenous echogenicity (24.1%), calcification (1.5%), capsular thickening (1.5%), and cystic change (19.7%). A significantly higher proportion of parathyroid carcinomas demonstrated heterogenous echogenicity (P = 0.022), capsular thickening (P = 0.023), and infiltrative margin (P < 0.0001) than benign parathyroid lesions. Of the 137 benign parathyroid lesions, 38 (27.7%), 76 (55.5%), 23 (16.8%) were avascular, vascular, and hypervascular, respectively. Of the 10 parathyroid carcinomas, 4 (40%), 3 (30%), and 3 (30%) of lesions were avascular, vascular, and hypervascular, respectively. The vascularity of the lesions did not differ significantly between the parathyroid carcinoma and benign parathyroid lesions (P = 0.281). CONCLUSION: Ultrasonographic features such as irregular shape, heterogeneous echogenicity, cystic change, and vascularity are nondiscriminatory features between benign or malignant lesions. Large lesion size together with the presence of calcification, capsular thickening, or infiltrative margin strongly raises the suspicion of a malignant parathyroid lesion, and management should be altered.

Ultrasound features of malignancy in the preoperative diagnosis of parathyroid cancer: a retrospective analysis of parathyroid tumours larger than 15 mm.

OBJECTIVE: Nearly all reported parathyroid cancers are >15 mm at presentation. The objective was to identify ultrasound criteria of malignancy in parathyroid lesions of >15 mm in size. MATERIALS AND METHODS: This study was approved by a local ethics committee. A retrospective review of patients identified from a database from 2004-2009 was performed. All patients underwent ultrasound imaging according to the protocol. Two trained observers categorized findings using the pre-determined features: shape, calcification, pattern of vascularity, local infiltration and internal lesion gray scale appearances. RESULTS: Sixty-nine patients (mean age 54.3 years, range 19-79 years; male = 16, female = 53) fulfilled the criteria of a parathyroid lesion >15 mm; 8/69 (11.6%) with parathyroid cancer and 61/69 (88.4%) with benign solitary parathyroid adenoma. A high positive predictive value (PPV) for cancer was identified for infiltration (PPV 100%) and calcification (PPV 100%), whilst a high negative predictive value (NPV) was found for the absence of suspicious vascularity (NPV 97.6%), a thick capsule (NPV 96.7) and inhomogeneity (NPV 100%). CONCLUSION: In lesions >15 mm systematic ultrasound assessment of specific features provides a valuable tool to identify parathyroid cancers before surgery.