Squamous cell carcinoma arising from lichen planus

We describe a middle-aged female patient who presented with a 1-year history of a thick-crusted plaque on an erythematous base of the left heel. Twenty years earlier, the patient was diagnosed with lichen planus and received treatment, leaving residual erythema on the heel. Over the past year, she noticed a progressive enlargement and desquamation of the erythema with a newly formed brown-yellow, hyperkeratotic and thick-crusted plaque in the centre, which was recalcitrant to empirical topical glucocorticoids, antibiotics and antifungals. Based on the clinical and typical histological findings, a diagnosis of squamous cell carcinoma arising from lichen planus was made.