Predictive value of pentagastrin test for preoperative differential diagnosis between C-cell hyperplasia and medullary thyroid carcinoma in patients with moderately elevated basal calcitonin levels

Medullary thyroid carcinoma (MTC) is a calcitonin (CT)-secreting neuroendocrine tumour originating from thyroid C cells. Serum CT concentrations are helpful in the early detection of MTC, while it is still unclear whether they can be used also for the differential diagnosis between MTC and C-cell hyperplasia (CCH), a precancerous condition in familial MTCs but with unclear clinical significance in sporadic MTCs. Nowadays, surgery is recommended in all patients with basal or pentagastrin (PG)-stimulated CT value of 100 pg/ml or more, without discriminating if they are affected with MTC or CCH only. The objective of this study was to investigate the utility of the PG test for CT in distinguishing CCH from MTC before surgery.