en Pediatric Hematology & Oncology Pediatric Hematology & Oncology گزارش مورد Case report <div style="text-align: justify;"><span style="line-height:2;"><span style="font-family:Times New Roman;"><span style="font-size:14px;"><strong>Background: </strong>&nbsp;Leukemia cutis (LC) is uncommon in children and may precede recognition of systemic leukemia. A solitary scalp mass with a normal blood count can be mistaken for a benign lesion.<br> <strong>Case Presentation: </strong>&nbsp;A 12-year-old girl had a six-month history of a right frontoparietal scalp mass initially considered a lipoma. The lesion was firm, alopecic, and approximately 2 &times; 2 cm. Complete blood count and peripheral smear were unremarkable. Skin biopsy showed a TdT-, CD19-, CD10-, CD34-, and PAX5-positive precursor B-cell infiltrate with a high Ki-67 index. Bone marrow contained 30.8% blasts with a B-lineage immunophenotype, establishing B-cell acute lymphoblastic leukemia (B-ALL). The scalp lesion nearly regressed after induction therapy. Although morphologic remission was achieved at end of induction, measurable residual disease (MRD) was 2.05%; MRD declined to 0.0066% at end of consolidation and was 0.0033% at last reported assessment.<br> <strong>Conclusion: </strong>&nbsp;Persistent or enlarging scalp lesions in children warrant tissue diagnosis even when peripheral blood findings are normal.</span></span></span></div> Leukemia cutis, B-cell acute lymphoblastic leukemia, Scalp mass, Extramedullary disease 59 63 http://ijbc.ir/browse.php?a_code=A-10-616-3&slc_lang=en&sid=1 Mohammadreza Bordbar Yes Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Reihaneh Sedghi No Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Shayan Bordbar shayanbor@gmail.com No Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.