Necrobiosis lipoidica: Squamous cell carcinoma can develop within nonhealing ulcers

Key Points

New York - The diagnosis of necrobiosis lipoidica (NL) may be straight-forward, but most experts agree that the treatment for this chronic granulomatous dermatitis is not as simple. Though rare, squamous cell carcinoma (SCC) can develop within NL, making these lesions even more challenging to follow.

Necrobiosis lipoidica is a chronic granulomatous condition with a distinctive clinical appearance, characterized by atrophic, yellow plaques with ecstatic blood vessels. It typically appears on the anterior shins, and the majority of cases occur in patients with diabetes. These lesions are sensitive to physical trauma, and can ulcerate. Ulcerations are slow to heal, especially in diabetics.

In the case of ulcers that do not heal with traditional woundcare, the physician should be suspicious that a possible SCC has either developed within the wound or caused the ulceration.

Slow healing

When wounds develop in NL, they heal slowly due to the inflammatory nature of the lesion. This is especially true when compounded with microvascular changes that occur in diabetic patients.

Therefore, wounds must be followed carefully. The decision to biopsy must be weighed against the risk of creating more damage to atrophic, poorly healing skin, according to Dr. Zeichner.

Case study

Recently, a 53-year-old insulin-dependent diabetic female with a 45-year history of NL presented to Dr. Zeichner and colleagues for follow-up on a chronic lower leg ulceration occurring in a NL lesion. The patient had pretibial, atrophic, telangiectatic yellow plaques on both lower extremities. The left leg ulcer was characterized by an area of central granulation tissue. A punch biopsy of the central granulation tissue was consistent with SCC. The patient subsequently underwent Mohs surgery, and the SCC was removed in a two-stage procedure that was followed by a full-thickness skin graft.

"Necrobiosis lipoidica lesions are atrophic, so it could be difficult clinically to diagnose a squamous cell cancer within the lesion. However, any surface changes, including scaling, crusting and ulceration, are important clues. Providers need to keep the possibility of a malignancy in the back of their minds when following these lesions," Dr. Zeichner tells Dermatology Times.

Pioneering work is being done at Mount Sinai Hospital's department of dermatology, exploring new avenues of therapy for NL. Dr. Zeichner has published success with intralesional etanercept, and is currently exploring the use of other biologic agents as well as photodynamic therapy for NL.

"While most dermatologists typically view NL as a cosmetic condition, the potential increased risk for malignancy within the lesion is fueling the need for better treatments," Dr. Zeichner says.