Background: Sweet syndrome with both histiocytoid pathology and giant cellulitis-like lesion feature is extremely rare and has only been reported once. Our case is different from the previous report because the cutaneous lesion was caused by local invasive irritation, which made it much more difficult to distinguish from cellulitis.
Case presentation: A 52-year-old male was diagnosed with myelodysplastic syndrome with multilineage dysplasia (MDS-MLD) associated with myelofibrosis (MDS-F) as well as angioneurotic edema of the tongue and floor of the mouth. Seven days after sternal aspiration, a cellulitis-like lesion was formed at the puncture site. Since he had neutropenia, history of glucocorticoid use and didn't keep the site dry and clean after aspiration, cellulitis was diagnosed, followed by broad-spectrum antibiotics and debridement. However, the lesion continued to expand, associated with blisters formation, accompanied by chills and fever. Blood cultures and blister smears didn't detect any pathogens. Biopsy of the lesion was performed and histiocytoid Sweet syndrome was diagnosed. He received prednisone treatment, and the fever relieved within 24 hours and the cutaneous lesion resolved within one week. He has had no recurrence during two-month follow-up.
Conclusions: This case can provide help for timely diagnosis and treatment and a reference for further summarizing the characteristics of this rare variant.