Endocrine Abstracts

Background: There is much debate about the best imaging modality for parathyroid adenoma. Parathyroid ultrasound is operator dependent and in skilled hands leads to localisation of tumour. Small adenomas can be difficult to detect and radiologists are helped by clinical and biochemical data to predict ease of adenoma detection. We investigated whether any factors could predict adenoma size.

Methodology: This was a retrospective CWS analysis of patients who had undergone parathyroidectomy between 2010 and 2013. Data collected included serum calcium, PTH, ALP, vitamin D, tumour volume on scan, tumour volume on histology. Linear regression analysis was performed and reported as odds ratio (=OR, 95% CI).

Results: There was a very close correlation between tumour volume on scan and histology (Pearson correlation 0.803, P<0.001). ALP and PTH was associated with tumour volume, ALP being more closely associated (0.016 (0.007, 0.025) and 0.019 (0.003, 0.034) respectively). There was no association between pre-op hypercalcaemia and tumour volume (OR 1.7(−.094, 4.36)). Vitamin D was checked in <50% of patients. Regression analysis with three blood tests (ALP, Ca, PTH), showed that ALP was the only independent predictor of tumour size (OR=0.012 (0.003, 0.022)).

Conclusion and discussion: There seems to be a correlation between adenoma size and histological volume suggesting excellent radiological expertise. The correlation between ALP and tumour volume may suggest that the presence of metabolic bone disease is a marker of adenoma size. PTH was also linked to tumour volume, indicating that this might also be a predictor of adenoma size.