SUN-332 The Silent Passenger: Papillary thyroid carcinoma in the setting of Acromegaly

Abstract Disclosure: F.R. Shaya: None. E.M. Alhussain: None. W. Taha: None. Increasing reports of patients with acromegaly have noted incidental discoveries of papillary thyroid carcinoma, which is the case for this report, emphasizing the potential need for routine thyroid screening in acromegaly management guidelines.A 42-year-old male presented with clinical features concerning for acromegaly , including facial changes, enlarged hands and feet, and soft tissue swelling. Laboratory evaluation confirmed elevated insulin-like growth factor 1 (IGF-1) levels, and magnetic resonance imaging (MRI) revealed an anterior pituitary macroadenoma. The patient underwent transsphenoidal pituitary resection.Histopathological analysis of the tumor showed a biphasic population of medium-sized epithelial cells, with some areas of necrosis. Immunohistochemical staining demonstrated strong reactivity for chromogranin, GH, thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH), consistent with a neuroendocrine origin. The Ki-67 proliferation index was low at 2%.During routine postoperative evaluation, an incidental thyroid nodule was detected. Fine-needle aspiration (FNA) confirmed the presence of papillary thyroid carcinoma. The patient had no known family history of thyroid cancer and was asymptomatic. He subsequently underwent total thyroidectomy without complications.The coexistence of acromegaly and papillary thyroid carcinoma in this patient raises important clinical considerations. Acromegaly is associated with elevated levels of GH and IGF-1, which have been implicated in promoting cellular proliferation and tumorigenesis. Several case reports have suggested an increased prevalence of papillary thyroid cancer in acromegalic patients, yet routine thyroid screening is not universally recommended in current guidelines.While definitive causative links between acromegaly and thyroid cancer remain under investigation, the role of IGF-1 in thyroid tumorigenesis warrants further exploration.This case presents the potential relationship between acromegaly and thyroid cancer, highlighting the importance of early thyroid evaluation in patients diagnosed with acromegaly. Incorporating routine thyroid ultrasound into standard evaluation protocols could facilitate the early detection and management of thyroid malignancies. Further prospective studies are necessary to refine surveillance strategies and determine whether thyroid ultrasound should be a formal recommendation in acromegaly management guidelines. Presentation: Sunday, July 13, 2025