Endocrine Abstracts

Introduction: Acromegaly is characterized by elevated levels of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), most often due to a pituitary tumor. Persistent high levels of these hormones lead to a constellation of signs and symptoms and systemic complications associated with increased mortality. A potential association between acromegaly and cancer has been hypothesized regarding colorectal, thyroid, and prostate cancers, but there are few or no descriptions for other kinds of tumors.

Case presentation: Male, 49 years old, presented with headache, multiple episodes of loss of consciousness, joint pain, profuse sweating. Clinical examination revealed acral enlargement, generalized thickening of the skin, prominent supraorbital ridges, nose enlargement, prognathism. Hormonal assessment showed increased levels of IGF-1 (2.8 x upper limit of normal, ULN) and high levels of nadir GH in the oral glucose tolerance test (OGTT, 10.3 ng/ml). All others anterior pituitary hormones were within normal range. Pituitary MRI revealed a hypophyseal mass with heterogenous signal (23/14 mm). The patient underwent surgical removal of the pituitary macroadenoma using transsphenoidal resection. The immunohistochemical (IHC) examination showed positivity for GH and prolactin (PRL). Three months after surgery, the patient presented active disease (IGF-1=1.8 x ULN, nadir GH in OGTT=3.24 ng/ml), with a small pituitary remnant (9/7 mm). The disease persisted uncontrolled after two years of treatment with Octreotide LAR up to 40 mg/28 days, Cabergoline up to 3 mg/week and Pegvisomant up to 40 mg/week (associated in the last three months, with good control of GH secretion). The patient developed severe obstructive sleep apnea documented using polysomnography. Fibroscopy reported a glossy, smooth tumor occupying completely the choanal quadrant and pegvisomant was withdrawn. Surgical intervention was performed, and the histopathological examination described a sessile polyp on the background of a chronic erosive rhinopharyngitis. IHC analysis revealed a positive cytoplasmic reaction for GH in tumoral cells. Two months after the nasopharyngeal tumor resection, IGF 1 was within normal range on somatostatin analogue and dopamine agonist.

Conclusion: Active acromegaly defined by GH excess and increased levels of IGF-1 contributes to mitogenesis, delayed apoptosis and malignant proliferation. In the current case, uncontrolled acromegaly was associated with a nasopharyngeal tumor presenting IHC positive expression for GH. This aspect could partially explain the decreased IGF-1 levels after surgical intervention and a better therapeutical response to standard medical treatment and could raise the hypothesis of a tumor invasion.