To the Editor:
A 34-year-old man presented with fever, easy bruising, and pancytopenia with increased peripheral blasts of 77%. Bone marrow biopsy showed hypercellular marrow with 80% to 90% involvement by acute promyelocytic leukemia (APL) with complex cytogenetics: 47,XY,t(4;17;18)(p16;q21,q25;q21.1),+8, ins(15;17)(q22;q21q25). He underwent induction chemotherapy with all-trans retinoic acid (ATRA) and idarubicin, which was complicated by differentiation syndrome that presented with fever and fluid retention. Discontinuation of ATRA and initiation of dexamethasone led to resolution of the symptoms. Complete hematologic and molecular remission was achieved after the induction chemotherapy.
Following a risk-adapted treatment protocol for consolidation therapy,1 he underwent an uneventful first cycle of consolidation therapy. On day 15 of the second cycle of consolidation therapy with ATRA and mitoxantrone he was hospitalized with a fever (temperature, 38°C) in a setting of neutropenia (absolute neutrophil count [ANC], 0/µL [reference range, 1500–7200/µL]). He was empirically treated with ceftazidime and vancomycin and maintained on prophylactic acyclovir and fluconazole. Routine workup was negative for infection. He became afebrile within 24 hours. With negative infectious workup, vancomycin was discontinued on day 17. On day 33 he again developed a fever (temperature, 38.8°C) when the ANC started to recover (570/µL). A new skin rash was noted at this time. Physical examination revealed generalized, nonpruritic, tender, pink papules and plaques with dusky centers and central pustules on the trunk as well as the upper and lower extremities. The palms and soles were spared. The rash was somewhat reminiscent of Sweet syndrome (SS). No vesicles, bullae, or erosions were seen (Figure 1). Repeat blood and urine cultures and chest radiograph were unremarkable. Ceftazidime was discontinued due to concern of drug-associated rash. Within the next 48 hours, the patient developed rigors and a worsening rash that led to reinitiation of broad-spectrum antibiotic coverage with meropenem and vancomycin. Computed tomography of the chest, abdomen, and pelvis did not show any evidence of infection or other abnormalities. Skin biopsy showed an acute folliculitis and multiple foci of mixed granulomatous inflammation consisting of histiocytes, lymphocytes, and neutrophils with focal necrosis present in the dermis, dermis-subcutis junction, and subcutis (Figure 2). Diagnostic features of vasculitis were not seen. Viral cytopathic features were not identified. Tissue culture and special stains including Gram, acid-fast bacteria, and Grocott methenamine silver stains were negative for infectious organisms in the biopsy. Both direct fluorescent antibody study and cell cultures for varicella-zoster virus, cytomegalovirus, and herpes simplex virus also were negative.
Figure 1. Rash on the left lower leg.
Figure 2. Skin biopsy revealed multiple foci of inflammatory reaction (A); acute folliculitis (B); and a mixed granulomatous reaction consisting of histiocytes, lymphocytes, and neutrophils with focal necrosis at the dermis-subcutis junction and subcutis (C)(H&E; original magnifications ×40, ×200, and ×400, respectively).