MON-414 Beyond the Graves’: A Twisted Tale of Hashimoto’s Hypothyroidism with Ophthalmopathy, Acropachy, and Elephantiasis

Abstract Disclosure: M. Manolas: None. T. Lu: None. A. Regan: None. B. Wong: None. Background: Hashimoto’s thyroiditis is the most common cause of hypothyroidism, characterized by autoimmune thyroid destruction and the presence of TPO antibodies. Thyroid associated ophthalmopathy and dermopathy are most commonly seen in hyperthyroid conditions like Graves' disease, but they rarely can occur in patients with hypothyroidism as well. In some cases, patients with autoimmune thyroid disorder may exhibit both thyrotropin blocking antibodies and thyroid stimulating antibodies. Shifts in concentration of these opposing antibodies can result in fluctuations of thyroid function and variable clinical manifestations.Clinical Case: A 38 year old woman with a history of longstanding hypothyroidism, obesity, and obstructive sleep apnea presented with weakness and shortness of breath. On arrival, she was hemodynamically stable, with a blood pressure of 169/105 mmHg, heart rate of 74 bpm, and body temperature of 36.8°C. She was at baseline mental status, without concern for myxedema coma. She denied a history of hyperthyroidism, radioactive iodine ablation or prior neck surgery. Laboratory data revealed TSH >100 uU/mL (ref. 0.30 - 4.20), Free T4 0.5ng/dL (ref. 0.6 - 1.5), Thyroglobulin (Tg) antibody 27.6 IU/mL (ref. <1.0), Thyrotropin Binding Inhibitor Immunoglobulin (TBII) >40 IU/L (ref. <2.0), Thyroid Stimulating Immunoglobulin (TSI) 250% (ref. <140%), and TPO antibody 3.2 IU/mL (ref. <5.0). Thyroid ultrasound showed normal thyroid tissue without discrete nodules or hypervascularity. Physical exam was notable for bilateral proptosis, periorbital edema, acropachy of both hands with digital clubbing and significant lower extremity elephantiasis nostra verrucosa (ENV). Radiographs confirmed the typical periosteal reaction of acropachy. She was initially treated with IV levothyroxine before transitioning to oral formulation. By discharge, her FT4 and TSH had improved significantly. Conclusion: This case is a unique presentation of Hashimoto’s thyroiditis with ophthalmopathy, dermopathy with ENV, and acropachy in the context of hypothyroidism with positive Tg, TSI and TBII antibodies. The absence of hyperthyroidism despite elevated TSI suggests underlying glandular destruction, likely from Hashimoto’s Thyroiditis, resulting in a lack of response to stimulatory antibodies while the TSI is contributing to the extrathyroidal manifestations of autoimmune thyroid disease. Acropachy is the rarest extrathyroidal manifestation, occurring in about 0.3% of patients with Graves’ disease. ENV, a severe form of thyroid dermopathy, is linked to high titers of TSH receptor antibodies, as seen in our patient. This case highlights the unusual overlap of thyroid-stimulating and thyroid-blocking antibodies, underscoring the need for further investigation into the mechanisms driving antibody shifts in autoimmune thyroid disease and its clinical manifestations. Presentation: Monday, July 14, 2025