[Treatment of pretibial myxoedema with pentoxifylline]

[Pretibial myxedema after Graves' disease: A differential diagnosis of lymphedema]

INTRODUCTION

Pretibial myxedema is a rare manifestation of Graves' disease, and pseudotumoral forms may be confused with lower limb lymphedema.

OBSERVATIONS

We reported 3 cases of pretibial myxedema in 2 women and 1 man, aged 72, 66, and 49 years, treated for Graves' disease 3, 25 and 32 years previously. Two patients were active smokers. Lymphedema diagnosis of the lower limbs was suspected in the presence of bilateral pseudotumoral lesions of the feet, toes and ankles and the presence of a Stemmer's sign (skin thickening at the base of the 2nd toe, pathognomonic of lymphedema). Lymphoscintigraphy in one case was normal, not confirming lymphedema.

CONCLUSION

Pretibial pseudotumoral myxedema is a differential diagnosis of lower limb lymphedema. This diagnosis is confirmed by questioning the patient about preexisting Graves' disease, the underlying etiology, to decide the appropriate treatment and to encourage cessation of smoking, which is a risk factor for pretibial myxedema.

[Graves' dermopathy on the big toe]

BACKGROUND

Localized myxoedema is a rare dermopathy in patients with Graves' disease. The pretibial area is the most commonly affected region but herein we present a case of myxoedema of the big toe.

PATIENTS AND METHODS

A 44-year-old male with Graves' disease ongoing for seven years presented bilateral ophthalmopathy and myxoedema of the big toes. The myxoedema was treated successfully with intralesional steroids.

DISCUSSION

The physiopathology of myxoedema involves fibroblast activation and glycosaminoglycan production. This activation could result from stimulation of TSH receptors at their surface by TSH receptor antibodies (TRAK) or from an inflammatory process. The pretibial topography may be related to the high frequency in this area of microtrauma, with modulation of the cytokine microenvironment.

CONCLUSION

The atypical localization seems to correlate with a Koebner phenomenon. Treatment of Graves' disease is generally insufficient to resolve the cutaneous problems. Topical corticosteroid therapy generally results in rapid improvement of recent lesions.