A 69-year-old man with a history of relapsed acute myeloid leukemia (AML) monocytic type presented with intermittent fever and fatigue 2 months after allogeneic stem cell transplantation (SCT). Post-SCT bone marrow biopsy specimen analysis at day 30 showed no evidence of leukemic cells and 99.5% donor cells. His home medications included acyclovir, fluconazole, and cyclosporine. Temperature on admission was 103.1° F, and other vital signs were unremarkable. Vancomycin and cefepime were started for possible infection. Complete blood cell counts with differential counts showed no evidence of peripheral blasts. Laboratory and imaging work-up—including chest radiographs, blood culture, fungal culture, urinalysis, sputum culture, respiratory viral panel, fungitell and galactomannan assay, coccidioidomycosis serology, and cytomegalovirus and human herpesvirus 6 polymerase chain reaction assays—were all negative. The patient was discharged with oral antibiotics after being afebrile for 72 hours. Thereafter, he had 2 more emergency department visits and was readmitted for recurrent fever. A thorough physical examination revealed 2 nonpruritic skin bumps on the right forearm and left calf that both measured 1.0 cm × 1.5 cm. Both bumps were soft without pigmentation or ulceration. Pathologic sampling of the respective lesions revealed a diffuse infiltration of large mononuclear cells with high nuclear-to-cytoplasmic ratio (Figure, A and B). Immunohistochemistry staining was positive for CD4 cells and myeloperoxidase (Figure, C and D)