Endocrine Abstracts

Introduction: In type-1 neurofibromatosis (NF-1) there is an increased risk of endocrine tumors, especially pheochromocytomas, whereas thyroid carcinomas seem to be extremely rare, with few cases reported in literature.

Subjects and methods: In order to investigate the frequency of hypercalcitoninaemia and medullary thyroid cancer (MTC) in patients with NF-1, we evaluated the thyroid gland morphology and function in 17 patients with NF-1 by i) neck US, ii) Fine Needle Aspiration (FNA) biopsy of the nodules detected at US and the measurement of calcitonin (CT) in wash-out fluid from FNA (CT-FNA), iii) serum CT at basal level and after stimulation with pentagastrin (CT-Pg) and iv) thyroid function.

Results: i) 10/17 (58.8%) had nodular goiter and ii) on the basis of cytology at FNA, 3/10 underwent total thyroidectomy with histological confirmation of malignancy in 2/10 patients (1 papillary thyroid cancer and 1 infiltrative squamous carcinoma); iii) only 1/17 presented an increase in basal CT with pathologically increased CT-Pg (>100 pg/ml) with an histological finding of C-cell Hyperplasia after thyroidectomy; iv) of the 16 remaining patients, CT-Pg was normal in 10 patients (<50 pg/ml), while 6 patients had a borderline response (50<CT-Pg<100 pg/ml) (Elisei et al. Journal of Clinical Endocrinology and Metabolism 2004); v) of the 6 patients with 50<CT-Pg<100 pg/ml, 5 had thyroid nodules and 2 had notably increased CT-FNA levels (745 and 789 pg/ml, respectively); vi) thyroid function was normal in all patients.

Discussion: The finding of goiter in 60% of NF-1 patients, of thyroid cancer in 11 and 40% of borderline/high CT-Pg suggest that an accurate study of thyroid gland in patients with NF-1 is mandatory and that thyroid diseases may be underestimated in the context of NF-1.