Sweet syndrome (SS) is an acute febrile neutrophilic dermatosis that is histologically characterized by an infiltration of the dermis by neutrophils. A 12-year-old adolescent female patient recently diagnosed with acute promyelocytic leukemia presented with fever and was hospitalized for antibiotic management after 22 days of being treated with a treatment protocol based on daunorubicin, all-trans retinoic acid (ATRA), and prophylaxis with dexamethasone, the patient developed erythematous skin lesions located mostly on the extremities. Lesions evolved into painful subcutaneous nodules, and one lesion evolved into a 2.5-cm blister with a purple and necrotic base. A skin biopsy was performed and showed neutrophilic dermatosis which confirmed the diagnosis of SS. The patient's clinical features complied with criteria for differentiation syndrome complicated by shock. Two days after ATRA was suspended, the patient presented resolution of the fever and skin lesions. SS is a rare neutrophilic dermatosis secondary to an innate immune disorder classified into four categories: classical (idiopathic), para-inflammatory, paraneoplastic or pregnancy-related. SS has been described in patients with acute myeloid leukemia in adults secondary to the use of drugs such as ATRA or as a part of a paraneoplastic syndrome. SS can occur exceptionally in children with myeloid leukemia secondary to the use of drugs such as ATRA.

Background: Children with incurable cancer can be treated with metronomic chemotherapy. The aim of this study was to describe the functional status in children with end-stage cancer who received metronomic chemotherapy. Procedure: An observational cohort study was designed with a convenience sample of patients younger than 18 years of age treated with metronomic chemotherapy between 2014-2020 at Hospital Civil de Guadalajara in Mexico. Results: Forty-three patients were included with a median age of 13 years. Metronomic chemotherapy was indicated most frequently in patients with lymphoblastic leukemia in ten cases (23.3%). Before metronomic chemotherapy, more than 70% of patients had disease progression after a second-line treatment. The median treatment duration was 4.2 months. Treatment was suspended in 39 patients, of which 33 patients died. The domain correlated with a lower score on the palliative performance scale at diagnosis was described in 28 cases (65.1%) according to activity level or evidence of disease, in 14 patients (32.5%) with ambulation, and in one patient (2.3%) with intake. According to their score 28/43 (65%) patients presented improvement one month after starting treatment. The McNemar test before and after one month of treatment with metronomic chemotherapy was statistically significant for these symptoms (P=0.00). We found that statistical significance was preserved during the first three months (p = 0.016) of treatment. Conclusions: The outpatient administration, good treatment adherence and few adverse effects make metronomic chemotherapy a valuable treatment option. In our experience, functional status improved significantly in the first three months of treatment.