Echographic diagnosis of pretibial myxedema in patients with autoimmune thyroid disease

Abstract

Salvi M, De Chiara F, Gardini E, Minelli R, Bianconi L, Alinovi A, Ricci R, Neri F, Tosi C, Roti E. Echographic diagnosis of pretibial myxedema in patients with autoimmune thyroid disease. Eur J Endocrinol 1994;131:113–19. ISSN 0804–4643 In the present study we have evaluated the use of pretibial ultrasound for the diagnosis of pretibial myxedema (PTM). We studied 76 patients, 58 with Graves' disease, 13 with Hashimoto's thyroiditis and five with idiopathic hypothyroidism. Thirty-two normal subjects were also studied as controls. Sixty-four patients had associated ophthalmopathy. The ultrasound scanner was equipped with 10-and 13-MHz probes. Punch biopsies were carried out in 11 patients and tissue sections examined on a light microscope. On clinical examination 21 patients (28%) had suspected PTM. By ultrasound, we measured the thickness of dermis and subcutaneous tissue (Dl) and that including only deeper dermis (D2) in normal subjects to define the echographic parameters of normal pretibial skin. We then found increased skin thickness in 25 patients (33%), with mean Dl and D2 values significantly higher than those measured in controls (p < 0.00001). The echographic study was positive in 20 patients with ophthalmopathy (31%). Ultrasound showed increased skin thickness in 16 of 21 patients (76%) with clinically suspected PTM. Histopathological findings confirmed the presence of PTM in all the patients who underwent pretibial skin biopsy. We believe that the measurement of pretibial skin thickness by ultrasound may be useful for revealing the presence of PTM. Mario Salvi, Cattedra di Endocrinologia, Università di Parma, Via Gramsci 14-43100 Parma, Italy