Endocrine Abstracts

Background: Parathyroid adenomas form a major proportion (80-85%) of the causative pathology in primary hyperparathyroidism (PHPT) followed by hyperplasia (10-15%) and cancers <1%. The only definitive treatment option for PHPT is surgery.

Aim: To determine the pickup rate and correlation of the imaging modalities (ultrasound (US) and Sestamibi (MIBI)) with histological diagnosis of parathyroid adenomas in patients with PHPT

Methodology: Between 01/03/2019 - 01/03/2020, 64 patients were seen for PHPT; 32 undergoing surgical management were retrospectively identified. The imaging findings, surgery type and histology results were recorded. Histological findings were coded to either adenoma, other parathyroid tissue (parathyroid hyperplasia/abnormal parathyroid tissue or possible adenoma) or non-parathyroid tissue. Histology data was available for 29 patients.

Results: The majority of patients underwent a targeted parathyroidectomy (65%), neck exploration (28%) and 7% other (cardiothoracic / private surgery). On the histology, 19 patients had a confirmed adenoma, 9 had other parathyroid tissue and 1 no parathyroid tissue was identified. 48% of patients had concordant imaging (71% adenoma, 29% other-PTH on histology); 17% US only (60% adenoma, 40% other-parathyroid); 17% MIBI only (80% adenoma, 20% other-parathyroid) and 17% negative scan (40% adenoma, 40% other-parathyroid, 20% non-parathyroid).

Conclusion: All patients with positive imaging (concordant or single modality) were found to have a parathyroid adenoma or other parathyroid tissue on histology. Where the imaging was discordant, MIBI identified more adenomas than US alone. Those with negative imaging, the majority of patients were still found to have an adenoma or hyperplasia. This indicates that the majority of patients referred for surgery had the appropriate diagnosis of PHPT. However, changes in the histology reporting may be required to more clearly identify the underlying pathology (adenoma vs hyperplasia). The small number of patients preclude definitive conclusions on which imaging modality has greater correlation with the histology outcome.