[Dangerous mimikry - cutaneous tumours appearing as ulcus cruris]

We report on a 83-year-old female patient which suffered from a chronic ulcer of the right leg for several years. She has been treated with standard wound dressings under the diagnosis of an ulcer due to chronic venous insufficiency.

A first biopsy showed a lower leg dermatitis and dermatosclerosis due to the chronic venous insufficiency. Not till a second biopsy was taken in the course of the disease, a sqamous cell carcinoma could be diagnosed. Staging procedures showed no metastases.

A wide excision including parts of tendon and bone was necessary. Finally a myocutaneous latissimus-dorsi-flap in combination with split skin graft was performed. A sentinel-node-biopsy was negative.

Differential diagnoses of chronic wounds on lower legs are diverse and are often missed in clinical routine. Typical causes like chronic venous insufficiency, peripheral arterial occlusive disease or diabetes are found via basic diagnostics, rare diagnoses like the existence of ulcerated skin tumors are often found with a delay which leads to a poor prognosis for these patients. Besides pre-existing tumors also a secondary malignant transformation can be observed, for example towards a squamous skin cancer from an originally vascular long-lasting leg ulcer. In case of recalcitrant leg ulcers despite exhausting all therapeutic options a histological investigation of a tissue sample should be performed and an initially diagnosed cause for the chronic wound has to be scrutinized.