Endocrine Abstracts

Introduction: Pretibial myxedema is a rare manifestation of Graves’ disease caused by local autoimmune attack of the connective tissue probably mediated by anti TSH receptor autoantibodies (TRab). Its prevalence changes between 0.4 and 5% in Graves ‘patients and usually is accompanied by opthalmopathy. The diagnosis requires physical examination and clinical suspicion and in doubtful cases biopsy may be performed.

Case 1: Sixty four years old female patient who has been taking methimazole treatment with the diagnosis of Graves’ disease for eight months came to the endocrinology clinic with the complaint of a lesion on the anterior face of lower third of right leg. At the dermatological examination, a plaque with a shiny surface, measuring five centimeters, looking like an orange peel was observed. Upon palpation, it presented a firm and non-depressible consistency. Patient had a history of active moderate orbitopathy and received iv steroid therapy (4.5 gr prednisolone in divided doses). The patient was euthyroid at the time of evaluation with methimazole 2 tb/day and Trab was 1.3 IU/l (at the time of diagnosis it was 135 IU/l). Histopathological incisional biopsy was performed and histopathology revealed accumulation of mucin in reticular dermis leading to separation of collagen bundles. Dermopathy was successfully treated topical corticosteroids.

Case 2: Thirty seven years old female patient admitted to the clinics with symptoms of palpitations, excessive sweating and weight loss. She was diagnosed to have Graves’ disease. Radioactive iodine uptake of the thyroid was increased and TRab was three times higher than the upper limit of normal range. She had reddish edema on the distal tibia and was referred to the dermatology clinics. Pretibial myxedema diagnosis was made clinically and the lesion disappeared completely with topical steroids.

Conclusion: Graves’ dermopathy is typically asymptomatic, they are rarely pruritic or painful. In severe cases, associated with acropathy, bone pain may result from an underlying periosteal reaction. In patients with high TRab levels and orbitopathy, we should make a proper physical examination and refer the patient to a dermatologist if the patients has a lesion and the diagnosis is equivocal.