Venous ulcers develop most frequently in the lower third of the calf where the major veins are most superficial and have their greatest curvature, especially around the malleoli. This area is most susceptible to early pitting edema from leaking capillaries followed by extravasation of red blood cells leaving behind hemosiderin and melanin that result in hyperpigmentation. These changes often precede lower leg leakage of fibrin and the woody fibrotic change called lipodermatosclerosis. (Dermatologists often use big words that no one else commonly uses, can spell, or can define.) To rule out coexisting arterial disease, clinicians need to check for a palpable pulse and that the handheld 8-MHz Doppler is greater than 0.9 or the audible handheld Doppler is multiphasic (biphasic or triphasic, not monophasic).1

The characteristic venous ulcer usually occurs in this lower gaiter region, is triggered by trauma, and has a serpiginous (wavy) margin with a granulation tissue base. It is less common to see slough or debris in the base requiring debridement. With appropriate compression and treatment of factors that could impair healing, a venous ulcer should decrease 30% by week 4 to heal by week 12.2

Ulcers with a yellow fibrous base or punched-out appearance or that are present in other regions of the lower leg or dorsum of the foot are more likely to have another diagnosis. The differential diagnosis includes mixed venous and arterial disease, inflammatory ulcers (vasculitis, pyoderma gangrenosum), infections, and malignancy. While determining the correct diagnosis, clinicians should consider the potential for malignant transformation.

In this issue, Khan and Wood completed a comprehensive review of the Marjolin ulcer. Wounds and scars are associated with persistent inflammation, promoting the 1.7% malignant transformation rate identified in the article. This transformation has also been documented in chronic osteomyelitis sinuses, therapeutic radiation injuries, and the margins of skin grafts. Expanding the original description, chronic wounds have more recently been associated with other malignant transformations including basal cell carcinomas, melanomas, and several subtypes of sarcoma. The lag time can be 30 years or more after an acute injury, and lower extremities are the most common site, where the lesions have an ulcer in the center, a raised wound margin, and surrounding induration. There is a less common (15%) exophytic form that has a better long-term prognosis.

If an ulcer is not healing at the expected rate or has any of the changes in the expanded Marjolin ulcer definition, single or multisite biopsies are necessary. If the expertise is available, biopsy sites may be guided by dermatoscope examination. This instrument is a handheld 10x microscope with a light, similar to an ophthalmoscope, used to examine microscopic features of the skin. Repeat biopsies may be necessary given suspicious clinical signs, even if there is an initial negative result from histology.

Diagnosis and excisional surgery should be prompt to avoid the consequences of aggressive malignant change and a poor prognosis. Be sure to check for regional lymphatic spread or distal metastases. All wound healing professionals need to be aware of the risk of malignant transformation and the potential characteristic clinical signs.

Recently, we conducted an interprofessional audit of our urban (Southern Ontario) community's nonhealing leg ulcer wounds. In these unpublished data, there were 123 patients with leg ulcers, and vascular ulcers (venous, arterial, mixed) were the most common. A minority of patients who had less common diagnoses (including malignant or inflammatory ulcers) were not diagnosed prior to their interprofessional assessment. Clearly, to achieve optimal outcomes and manage malignant wounds in their early stages, it is important for primary care providers to have access to an experienced interprofessional wound assessment team. The team needs to maintain suspicion of malignancy. With an integrated and coordinated healthcare approach, better outcomes are possible at a lower cost. Do you have timely access to an interprofessional wound care assessment team?

R. Gary Sibbald, MD, DSc (Hons), MEd, BSc, FRCPC (Med Derm), FAAD, MAPWCA, JM

Elizabeth A. Ayello, PhD, MS, BSN, RN, CWON, ETN, MAPWCA, FAAN

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