FAP is a dominant autosomic syndrome, due to mutation of the APC oncosuppressor gene, characterised by adenomatous polyps at the colonrectal level, that progres to malignant degeneration. FAP extraintestinal manifestations include, although rare, the thyroid nodules and tumours. Neck ultrasound (US) is routinely useful to identify thyroid nodules, but the characterisation of their nature requires the cytology by a FNAb. The exact incidence of the thyroid tumours on FAP syndrome is unknown.
Aim: To evaluate the prevalence of thyroid nodules and tumours in a group of FAP patients.
Subjects and methods: Forty-six consecutive FAP outpatients (25♀54%, 21 ♂46%; mean age 46.76±DS 13.96 years) underwent neck US. The lesions above 5 mm of diameter underwent FNAb. The control group was of 599 subjects who underwent FNAb because of thyroid nodules.
Results: From the 41 FAP patients included in the study, 18 (43.9%) (13♀, 5♂) showed thyroid nodules. The FNAb was performed on 12 FAP patients with thyroid nodules (66%; 8♀, 4♂): 2♀ (16.67%; mean age 34.05 years) had a diagnosis of papillary thyroid carcinoma. From the 599 FNAb of the control group 23 (3.8%) had a diagnosis of thyroid carcinoma (6♂-1% and 17♀-2.8%; mean age 48.88±DS 14.83 years).
Conclusion: The nodular goiter is very common in FAP (43.9%). Furthermore, cytology at FNAb highlights as the prevalence of thyroid tumours is higher in FAP group (16.67%), also when compared with a control group, selected from a iodine deficient area with an high incidence for thyroid carcinoma (3.8%). These data show a possible correlation between the two diseases and suggest the need for a careful follow-up of thyroid lesions in patients with FAP, by means of both neck US and FNAb.
03 - 07 May 2008
European Society of Endocrinology