The Pink Doughnut Sign—A Clinical Clue to Recognize Basal Cell Carcinoma Presenting as Chronic Leg Ulcer

Abstract

Chronic lower leg ulcers (LLUs) are a very common and associated with a high subjective and economic burden. They can be caused by a variety of factors. We have observed a common clinical feature in patients suffering from LLUs, which ultimately proved to be basal cell carcinomas (BCCs). We have nicknamed this sign “the pink doughnut sign.” The pink doughnut sign can aid in the early recognition of such BCCs, which is crucial to prevent unnecessary suffering, treatment costs, and poor local outcomes.

Dear Sirs,

Chronic lower leg ulcers (LLUs) are very common and associated with a high (or substantial) subjective and economic burden. They can be caused by a variety of factors, (see Figure 1) ¹ with chronic venous insufficiency, peripheral arterial occlusive disease, prolonged pressure and diabetes being the leading causes. ¹ One of the challenges for clinicians treating LLUs is recognizing less common etiologies including calciphylaxis, pyoderma gangrenosum or Martorell hypertensive ischemic leg ulcer. In particular, ulcerated skin cancer may be missed including basal cell carcinoma (BCC), which is the most frequent skin cancer on the lower extremities. ² Early recognition of such BCCs is crucial to prevent unnecessary suffering, treatment costs and poor local outcome.

Figure 1.

Lower leg ulcers: predilection sites and typical clinical manifestation of the most common causes.

When reviewing several cases of patients with nodular and/or sclerosing BCC treated for “chronic venous and/or diabetic lower leg ulcers,” we recognized two potential clinical indicators (see Figures 1 and 2):

“Atypical” ulcer localization. According to our experience and that of other authors, BCCs can often be observed at sites atypical for venous, diabetic, arterial, or pressure-related ulcers.^1,2

A perilesional pinkish, scarred, firm rim sometimes accompanied by pearly nodules and telangiectasias within the ulcer. As this pattern is usually not seen in lower leg ulcers of other etiologies and we have also found them in other publications and textbooks In light of its resemblance to a pink doughnut, we propose coining the term “pink doughnut sign” as a mnemonic aid for clinicians.

Figure 2.

Pink doughnut sign: examples of sclerosing basal cell carcinomas presenting as lower leg ulcers, typically a pinkish, scarred rim can be seen, sometimes associated with pearly nodules and telangiectasias.

The pink doughnut sign can help in early recognition of such BCCs.