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Case Reports

Abstract

Leukemia cutis (LK) is rare but crucial for prognosis. Among LK subtypes, involvement by acute lymphoblastic leukemia/lymphoma (ALL) is exceptionally rare, especially in pediatric patients.A 9-year-old girl presented with a left temporal facial rash, persisting for two weeks until biopsied. Meanwhile, she was evaluated for a several month history of left peri-parotid lymphadenopathy. The rash was initially clinically unrecognizable except on MRI. Vital signs remained stable. Antibiotic treatment was unsuccessful. The rash biopsy revealed dense diffuse dermal infiltration with enlarged lymphoid cells. Immunostaining showed diffuse positivity for CD19, PAX5, TdT, and CD34 in lesional cells, suggestive of cutaneous involvement by B-cell ALL. The left parotid gland was also involved. Other lab tests revealed pancytopenia, increased LDH, and 50% blasts in the blood and bone marrow. FISH analysis showed trisomy and Tetris of Chr4, and trisomy of Chr10.Leukemia cutis is rare and indicates a poor outcome. Clinically, presentations vary from localized to diffuse, flesh-colored papules to erythematous patches or plaques, mostly on the face and lower extremity. The incidence of LK varies among different types of leukemias. In pediatrics, the highest incidence is in acute myeloid leukemia in very young children, with concomitant skin lesions in 30% of cases. Skin infiltration by ALL blasts is uncommon and mostly associated with mixed leukemia gene rearrangement on Chr11. The combination of lymphadenopathy and facial rash in children should prompt clinicians to conduct a more thorough examination, as it might signal a more serious illness with implications for prognostic evaluation.