Endocrine Abstracts

Background: Acromegaly is a chronic rare disease induced by persistent hypersecretion of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) in adult patients. Several studies have associated acromegaly with an increased risk for developing different benign or malignant tumors.

Case presentation: A 33-year old female patient was diagnosed with acromegaly due to a large pituitary macroadenoma, in 2009. In the same period, she was also diagnosed with a very large and compressive nodular goiter with retrosternal extension and underwent a subtotal thyroidectomy. The pathological exam established that it was a papillary thyroid carcinoma (PTC). Therefore, two further surgeries were performed for the complete removal of the thyroid tissue. The pituitary adenoma was treated 6 months later through endoscopic transsphenoidal surgery, but a residual tumor mass remained in the left cavernous sinus, that was managed by external radiotherapy, followed by the administration of Somatostatin analogues (SMA) for six years. The patient developed thyrotropic and gonadotropic insufficiency after the neurosurgical intervention. Radioiodine therapy was necessary for thyroid carcinoma, but the administration of Thyrogen was mandatory due to the suppressed TSH induced by pituitary insufficiency. The evolution of the case was favorable under therapy and the patient is now in a satisfactory condition, with a good quality of life. The Thyroglobulin level is undetectable (0.04 ng/dl) and the last IGF-1 value, four months after discontinuation SMA, was normal (103, NV 58–219 ng/ml).

Discussion: This case present one patient from our acromegalic series, who was detected with PTC in the moment of diagnosis. Many studies reported a high prevalence of thyroid cancer, between 1.2–11% among acromegalic patients. Sustained exposure to high serum IGF-1 levels seems likely to play a role in the development of the malignant disease, by stimulating the proliferation of different cells and by inducing an antiapoptotic effect on thyroid follicular cells. Some studies suggested a role for different factors like pituitary radiotherapy, obesity, insulin resistance, IGF-binding proteins, in development of thyroid cancer.

The diagnosis and the management of this case were difficult and challenging, but the evolution of this case was favorable, with cure of diseases, PTC and acromegaly.

Conclusion: A careful evaluation and management allow a favorable evolution in this case. Patients with acromegaly should be routinely screened for thyroid pathology at first evaluation, to allow an earlier detection of associated thyroid disease.