Leiomyosarcoma presenting as 'idiopathic' unilateral lower limb lymphoedema.

A 74-year-old woman presented with an 8-year history of unilateral swelling of her right lower limb, which was thought to be 'idiopathic' lymphoedema until she noticed a painless swelling in her right groin. Physical examination showed a painless, non-pulsatile, deep-seated mass in her right proximal thigh with significant lymphoedema distally. MRI scan showed a large mass at her right inguinal region, involving the common femoral vein. Histological examination on complete excision revealed leiomyosarcoma. It is important to exclude proximal obstructive lesion before making a diagnosis of unilateral idiopathic lower limb lymphoedema.