Cutaneous acute myeloid leukemia (leukemia cutis) mimicking pernio

Summary: Patients who have advanced leukemia may rarely develop skin involvement, termed leukemia cutis. We report a case of leukemia cutis presenting with the clinical picture of pernio and which subsequently recurred in the same pattern after treatment. A 64-year-old woman with AML in remission was hospitalized to initiate chemotherapy for a confirmed AML relapse. Dermatology was consulted to evaluate painful, purple papules on her bilateral toes that had been present for one week. Punch biopsy of the lesion showed a dense superficial, deep perivascular, and interstitial mixed inflammatory infiltrate and was initially interpreted as pernio. However, given the patient’s known AML, additional work up was performed and identified a population of larger cells with finer chromatin and prominent nucleoli that stained positive for CD45, CD43, CD33, and CD117, and negative for CD34. A diagnosis of cutaneous AML was rendered. Ten months later, the patient presented to outpatient dermatology with painful, violaceous macules and plaques on the hands and feet. Biopsy again showed histologic findings suggestive of pernio. Cutaneous manifestations of leukemia cutis may rarely present as pernio both clinically and histologically. This case highlights the importance of clinical history in making an accurate diagnosis when the findings mimic benign disease.