Endocrine Abstracts

Introduction: Thyroid hemiagenesis (TH) is characterised by congenital absence of one thyroid lobe.

Aim: To assess possible association between TH and concomitant alterations of other structures derived from pharyngeal apparatus, which might potentially impact calcium-phosphate balance.

Materials and methods: Studied group: 20 patients with TH. Control group: 20 subjects with bilobed thyroid, matched for age and gender. Serum concentrations of total calcium, parathormon and calcitonin were measured. Additionally, an immunohistochemical expression of calcitonin, chromogranin A (chA), somatostatin, nueron-specific enolase (NSE) and calcitonin gene-related peptide (CGRP) was evaluated in surgical specimens from patients with TH and subjects with normal thyroid.

Results: There were no significant differences between concentrations of total calcium, parathormone and calcitonin between patients with TH and subjects with bilobed thyroid (total calcium: 9.62±0.8 mg/dl in TH vs 9.89±0.6 mg/dl in controls, P=0.331; parathormon: 40.99±16.8 pg/ml in TH vs 42.96±14.4 pg/ml in controls, P=0.978; calcitonin: 6.84±3.8 pg/ml in TH vs 8.54±6.3 pg/ml in controls, P=0.408). Positive staining for calcitonin was demonstrated in 3/8 (37.5%) of thyroid sections from patients with TH, while only in 2/33 (6.06%) of sections from control patients (P<0.005). All sections from patients with TH positive for calcitonin, also expressed chA, NSE and CGRP. Two sections from control subjects, positive for calcitonin, presented additionally positive reaction for chA and one of them also for NSE. None of them however, presented positive staining for CGRP and somatostatin. Out of three TH sections, in one hyperplasia of parafollicular cells of medium grade and of high grade in another one could be detected, in comparison to control sections, where hyperplasia of C-cells of low and medium grade was observed.

Conclusions: The study provides first immunohistochemical demonstration of the presence of parafollicular cells in subjects with TH. TH was associated with slightly enhanced C-cells hyperplasia in comparison to control specimens, what might indicate compensative proliferation of parafollicular cells. However, calcium-phosphate balance seems not significantly affected.