Primary aim of the study : to evaluate the prevalence of ulcerated cutaneous carcinoma or malignant degeneration, in leg ulcers, presumed of vascular origin and without evidence of healing despite 3 months of adequate treatmentSecondary aims of the study : to evaluate the interest of immunostainings for desmogleins 1-2 and p16 on biopsies to differentiate between pseudo epitheliomatous hyperplasia and squamous cell carcinoma ; and the prognosis of diagnosed carcinomas at 12 monthsStudy hypothesis : systematic biopsies of hard-to-heal leg ulcer may help to detect ulcerated carcinomas misdiagnosed as vascular ulcer or malignant degeneration of leg ulcer.

Prospective multicentric inclusion of 150 patients with leg ulcers without any evidence of healing (no change or increase of ulcer area) despite 3 months of adequate treatment The study population consisted of consecutive patients with one or more leg ulcers, diagnosed as related to venous insufficiency, associated or not with concomitant arterial insufficiency. All patients undergo a standard treatment including compression therapy adapted to the ankle brachial index and a local treatment depending on the wound stage.At inclusion, systematic punch biopsies (5-6 mm) are taken as part of routine clinical care under local anaesthetic by an experienced clinician: 1 to 2 biopsies in the edges and 1 to 2 biopsies in the wound bedSpecimens are transported in formalin solution to the usual pathology laboratory of the investigator. At the end of the study, specimens will be sent for immunostainings in a single pathology laboratory (Rouen, France)Treatments and/or other investigations are decided by the investigatorAt 12 months of usual follow-up, final diagnosis and prognosis are noted in the study file by the investigator.

Inclusion Criteria:

• leg ulcer of more than 3 months of duration
• leg ulcer presumed of vascular origin
• adequate etiologic treatment since 3 months
• absence of evidence of healing : absence of reduction of wound area or increase in wound area and/or in depth

Exclusion Criteria:

• hypertensive ulcer
• vasculitis
• treatment by cytotoxic agents or steroids in the previous 3 months

Patients with one or more leg ulcers, diagnosed as related to venous insufficiency, associated or not with concomitant arterial insufficiency.