Relapsing-remitting painful masses of the skeletal muscle

A 59-year-old male patient complained, from age 36, of insidious appearance in several weeks of a circumscribed painful mass, single or multiple, under the skin with hard consistency on palpation. At first, these masses were localised on sural aspect of the legs, thereafter on arms, thighs and, occasionally, on trunk and face. They had a diameter ranging from 3 cm to 5 cm and the overlying skin tissue was normal. Pain might increase with movement causing functional limitation of the corresponding limb. In the first years, they spontaneously remitted within 2–3 months, successively in 6–7 months. Onset of these lesions was never preceded or accompanied by systemic symptoms such as fever, …