Leukemia Cutis: An Unusual Presentation of Acute Lymphoblastic Leukemia in a Child

Leukemia cutis (LC) is a nonspecific word used for cutaneous infiltration of leukemia, which is a rare presentation of acute lymphoblastic leukemia (ALL), and always a harbinger of poor prognosis. We report a case of LC in a 5-year-old boy with a past medical history of ALL (L1) presented with multiple asymptomatic oval or annular red patches and plaques on his thighs, buttocks and back waist, and part of them were scaling lesions. A biopsy was performed and histopathological examination showed that medium-sized atypical cells with round to oval contours, scant cytoplasm, and finely dispersed chromatin infiltrated into the dermis and subcutis, and the perivascular and periadnexal areas were involved. Immunophenotyping showed that the atypical cells were positive for CD45, CD3ε, CD99, and Ki67 (about 70%). Considering the patient's medical history and the histopathology, the patient was diagnosed with LC.