12562 Extraocular Muscle Enlargement With Proptosis In A Patient With Non Thyroidal Disease

Abstract Disclosure: S.S. Bantu: None. P.N. Kabir: None. A. Gondhi: None. T.B. Vaughan: None. Extraocular muscle enlargement with proptosis in a patient with Nonthyroidal disease Introduction: Majority of cases with extraocular muscle enlargement (EOME) is due to Graves’ disease, commonly in about 95% cases and another 5% make up other causes including inflammatory, neoplastic, vascular, infectious and acromegaly. We present a patient with sudden loss of vision, retroorbital pain with visual field deficits found to have EOME and subsequently a pituitary macroadenoma on imaging. Case: We present a 54-year-old male with history of hypertension, obstructive sleep apnea and morbid obesity who presented to us with complains of left sided vision loss. Patient was evaluated by ophthalmology and noted to have unilateral, left-sided, change in visual acuity. Physical exam was notable for macrognathia, skin tags, enlarged hands, excessive sweating. MRI brain revealed bilateral EOME with proptosis and a pituitary macroadenoma measuring 1.5x1.7x1.3cm, abutting the pre-chiasmatic left optic nerve. On biochemical evaluation he was noted to have elevated IGF1 of 979 confirming the diagnosis of acromegaly. ((hemoglobin A1C of 5.5%, prolactin 5.1, FT4 0.89, TSH 0.692, total testosterone 61, IGF1 level was 979)). He underwent transsphenoidal resection of the pituitary macroadenoma. Pathology showed sparsely granulated somatotroph adenoma. Discussion: Acromegaly has an incidence of 3-4 cases per million per year. The characteristics of the disease are due to chronic growth hormone hypersecretion resulting in the excessive growth of tissue due to the stimulation of insulin-like growth factor 1 (IGF-1). EOME with proptosis in acromegaly is seen rarely. Visual symptoms may manifest as visual field deficits due to compression of the optic pathway in 18-25% cases, increased intraocular pressure, increase in corneal thickness and a diffuse symmetrical enlargement of the extraocular muscles which cannot be distinguished from thyroid orbitopathy on imaging. The degree of enlargement appears to correlate with the duration of the disease rather than the levels of IGF1. EOME improves with the treatment of acromegaly. Although visual symptoms may be a rare presentation of acromegaly, if the clinical suspicion exists, one may consider obtaining an IGF-1 level to complete the evaluation of EOME if the thyroid levels are normal. Presentation: 6/3/2024