Cytogenetic and Molecular Characterization of Sweet's Syndrome in Patients with Acute Myeloid Leukemia.
Authors: Kazmi Syed M. , Kantarjian Hagop M. , Tran Kathy M. , Cortes Jorge E. , Ravandi Farhad , Borthakur Gautam , Jabbour Elias J. , Faderl Stefan , Garcia-Manero Guillermo , Kadia Tapan M. , Daver Naval , Pierce Sherry A. , Nazha Aziz , Quintas-Cardama Alfonso , Pemmaraju Naveen 
Published: October 2019

Abstract
Abstract 2587

Background:
Sweet's syndrome (SS), also known as acute febrile dermatosis, has been associated with hematologic malignancies including acute myeloid leukemia (AML). We sought to identify the disease characteristics of AML patients (pts) who develop SS, and to report the cytogenetic (CG) and molecular genetic (MG) abnormalities observed.

Methods:
We conducted a retrospective review of charts of newly diagnosed AML pts that underwent induction chemotherapy and had follow up at our institution. Pts with SS were identified if both the clinical signs and symptoms and a biopsy of the skin lesion were consistent with SS. CG and MG abnormalities are reported here as part of our descriptive analysis.

Results:
Between years 2000 to 2011, we identified a total of 2178 newly diagnosed AML pts that underwent induction chemotherapy and had follow-up at our institution. During this time, 697 pts (32%) underwent skin biopsies in the course of their AML treatment and follow-up. 21 pts (1% of all pts and 3% of all who underwent skin biopsy) demonstrated signs and symptoms and had skin biopsy consistent with SS. Table 1 summarizes the baseline characteristics of pts with AML at the time of dx of SS, including the CG and MG abnormalities observed. Myelodysplastic syndrome (MDS) prior to diagnosis of AML and SS was present in 9 pts (43%). CG analysis revealed diploid karyotype in 7 pts (33%), deletion 5p in 8 pts (38%; 4 pts had del5p as sole abnormality, and 4 pts with del5p as part of other accompanying/complex CG) and 4 patients had complex CG (19%). Most common MG abnormality was seen in the FLT3 gene, found in 7 out of 18 pts (39%) tested (FLT3 –ITD present in 4 pts while mutation of FLT3 codon 835 occurred in 3 pts). In addition, two out of 7 (28%) pts tested, had NPM1 gene mutation (one pt had concomitant FLT3 gene mutation). Other CG and MG abnormalities are summarized in Table 1. Eight pts (38%) with SS received systemic steroids for treatment, 1 pt (5%) received topical steroids while 19 (90%) received antibiotics and supportive care. The treatment for SS was effective in 16 out of 16 pts (100%) for whom follow-up information was available. Three pts required multiple courses of steroids while 5 pts required one course of steroids. The median time to improvement reported in the signs and symptoms of SS was 14 days (range 4–153). The median overall survival of AML pts who developed SS during course of their management was 14 months (95% confidence interval 12.6 – 15.4 months).

Conclusions:
SS is a frequent occurrence among AML pts as compared to its incidence in the general population. It can occur in AML pts during all phases of the disease. In this retrospective review, we found that SS frequently occurs in AML that has developed in the setting of prior MDS and where leukemic cells carry CG and MG abnormalities of del5p and FLT3 gene respectively.

Disclosures:
No relevant conflicts of interest to declare.