NODULAR PRETIBIAL MYXEDEMA FOLLOWING TREATMENT OF GRAVES’ DISEASE

Abstract

INTRODUCTION/BACKGROUND
Pretibial myxoedema (PM) is an uncommon manifestation of Graves' disease (GD). Typically, thyroid dermopathy may present as non-pitting oedema with indurated skin giving a ‘peau d’orange’ appearance. Less commonly, patients may present with other variants such as plaques, nodules and elephantiasic type lesions. We report a case of biopsy-proven PM in a patient with GD.

CASE
An 80-year-old woman presented with multiple painless nodules over both shins with gradual increase in size over 6 months. She had a history of hypertension and difficult-to-manage GD, complicated by thyroid storm, atrial fibrillation, and heart failure. Her thyroid function fluctuated from hypo- to hyperthyroidism within weeks. She refused radioactive iodine ablation and was subsequently controlled with a block and replace regimen. She did not have any constitutional symptoms, preceding trauma, or insect bite. Clinically, she was euthyroid and did not have any active thyroid eye disease. On examination, there were multiple ill-defined, firm, nontender, flesh-coloured nodules over both shins. Her FT4 was 18.12 pmol/L (12.0 - 22.00) and TSH <0.005 m IU/L (027 – 4.20). A punch biopsy revealed fragmented collagen fibres with conspicuous mucin deposits over the reticular dermis and subcutaneous layer, consistent with PM. She was started on potent topical corticosteroids with marked improvement in her skin lesions.

CONCLUSION
Thyroid dermopathy can present in an atypical manner, hence, physicians should be aware of this. Treatment of hyperthyroidism may not have any significant effect on the cutaneous lesions. PM may occur even after successful control of the disease.