Endocrine Abstracts

Background: Acromegaly is associated with increased prevalence of thyroid diseases, particularly of differentiated thyroid carcinoma.

Aim: To assess prevalence of thyroid diseases and thyroid cancer in patients with acromegaly.

Patients and methods: Forty (10 M/30 F) acromegalic patients, 14 residents in iodine deficient areas, aged 47±12.8 years, were retrospectively reviewed. Mean duration of acromegaly was 7.6±9.5 years and median post diagnosis follow-up was 4.1 years. GH, IGF1 were measured by chemiluminescence (Liaison), TSH, FT₄ by immunometric assays (Immulite). Thyroid ultrasonography was performed in all cases, thyroid scintigraphy was performed when indicated; fine needle aspiration biopsy (FNAB) was performed in suspicious nodules, according to current guidelines.

Results: Thyroid abnormalities were present in 28 patients (70%) in our series: diffuse goiter in 8 patients (20%), simple nodular goiter in 5 patients (12.5%), nontoxic multinodular goiter in 10 patients (25%), toxic multinodular goiter in 4 patients (10%), Graves’ disease in one patient (2.5%); thyroid carcinoma was found in 3 patients (7.5%). Patients with thyroid nodules larger than 1 cm had significant longer acromegaly duration (6.1±3.6 years) than patients without nodules or nodules less than 1 cm (2.1±1.5 years), P=0.008. Histological type in patients with thyroid carcinoma was follicular variant of papillary thyroid carcinoma in all three cases: 2 microcarcinomas and one macrocarcinoma. All three thyroid carcinomas patients underwent total thyroidectomy and radioiodine treatment (mean cumulative dose 181.7 mCi ¹³¹I) and were in stable remission.

Conclusion: Due to increased prevalence of differentiated thyroid carcinoma, active screening for thyroid abnormalities is mandatory both in iodine sufficient and deficient areas, especially in patients with longer duration of acromegaly.