Perforating necrobiosis lipoidica

Perforating necrobiosis lipoidica (PNL) is a very rare variant of necrobiosis lipoidica (NL), almost always associated with diabetes. A non-diabetic 43-year-old man referred to us with a gradually enlarging plaque on his forehead. The patient was initially diagnosed with cutaneous tuberculosis based on the histopathologic findings, but failed to respond to antituberculosis therapy. Upon further evaluation and observation of the transepidermal elimination of degenerated collagen in the pathology slides, we rendered a diagnosis of PNL. The patient underwent successful treatment with topical tacrolimus and systemic hydroxychloroquine