7854 Ablation Aberration: A Case of Thyroid Dermopathy Exacerbation in a Filipino Male Following Radioactive Iodine Ablation and Total Thyroidectomy Improved by Weekly Intradermal Long-Acting Glucocorticoid Injection

Abstract Disclosure: K.T. Lim: None. O.C. Dampil: None. Ablation Aberration: A Case of Thyroid Dermopathy Exacerbation in a Filipino Male Following Radioactive Iodine Ablation and Total Thyroidectomy Improved by Weekly Intradermal Long-Acting Glucocorticoid Injection Introduction: Thyroid dermopathy (TD) represents an unusual extrathyroidal presentation of Graves' disease (GD), impacting about 0.5–4% of patients. RAI treatment for hyperthyroidism is known to progress Graves' ophthalmopathy. RAI-induced TD exacerbation, however, is rare in literature. Here, we present a case of worsening TD and ophthalmopathy in a Filipino patient with GD who underwent definitive therapy for persistent hyperthyroidism. Clinical Case: A 44-year-old man with GD had bilateral lower extremity indurated, mildly erythematous plaques for 4 years. Hyperthyroidism persisted despite methimazole compliance, so he underwent RAI ablation two years earlier, total thyroidectomy a year later, and has been on levothyroxine since. Despite definitive treatment, his extrathyroidal symptoms worsened. A punch biopsy of the skin lesions revealed upper and mid-lower dermis mucin deposition, with occasional spindle-shaped and stellate fibroblasts, and mast cells. These histopathologic findings were consistent with pretibial myxedema. We assessed his thyroid function and found he was euthyroid with normal TSH (3.1 μIU/mL; reference range 0.27-4.20) and an elevated TRAb (35.73 IU/L; reference range <1.75). Physical examination revealed thickened skin, cobblestone-like plaques, and non-pitting edema on the pretibial, ankle, and pedal areas. A 3.5-cm-diameter, circumscribed, orange-peel-textured, indurated plaque covered his left ankle. Fluocinolone acetonide 0.025% w/w ointment was initiated. After 3 weeks, his cutaneous symptoms improved by 35%, albeit his left ankle circumscribed plaque improved marginally. Triamcinolone acetonide 40 mg/mL was injected into this and other nodular lesions at 4mg (0.1 mL) per 1-cm-diameter circular region. Each dose was equally dispersed by multipoint intradermal injections using a 1 mL syringe with a 0.5”x 25G needle. A week after intralesional triamcinolone injection and continuous topical steroid application on the non-nodular lesions, a 70% improvement in cutaneous manifestations was observed (from baseline) with the plaques becoming thinner and softer. After three weekly intradermal steroid injections, the circumscribed plaque had flattened (with residual hyperpigmentation), and the other plaques and nonpitting edema dissipated. Conclusion: Our experience with this patient highlights a paradoxical TD exacerbation following RAI ablation and definitive surgery for persistent hyperthyroidism in GD. It also reveals that weekly administration of multiple subcutaneous injections of a long-acting glucocorticoid alleviates lesions where topical ointment does not. Presentation: 6/1/2024