ECHOGRAPHIC DIAGNOSIS OF PRETIBIAL MYXEDEMA IN PATIENTS WITH AUTOIMMUNE THYROID-DISEASE

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 wi th idiopathic hypothyroidism. Thirty-two normal subjects were also stu died as controls. Sixty-four patients had associated ophthalmopathy. T he ultrasound scanner was equipped with 10-and 13-MHz probes. Punch bi opsies were carried out in 11 patients and tissue sections examined on a light microscope. On clinical examination 21 patients (28%) had sus pected PTM. By ultrasound, we measured the thickness of dermis and sub cutaneous tissue (D1) and that including only deeper dermis (D2) in no rmal subjects to define the echographic parameters of normal pretibial skin. We then found increased skin thickness in 25 patients (33%), wi th mean D1 and D2 Values significantly higher than those measured in c ontrols (p < 0.00001). The echographic study was positive in 20 patien ts with ophthalmopathy (31%). Ultrasound showed increased skin thickne ss in 16 of 21 patients (76%) with clinically suspected PTM. Histopath ological findings confirmed the presence of PTM in all the patients wh o underwent pretibial skin biopsy. We believe that the measurement of pretibial skin thickness by ultrasound may be useful for revealing the presence of PTM.