A 54-year-old woman presented in the Internal Medicine department for painless, erythematous lesions in the dorsum of 5th finger of the right hand, resembling neutrophilic dermatosis. The lesions had spontaneously appeared 2 months prior and the patient only reported fatigue, without other symptoms. She denied any past medical history and chronic medication.
Laboratory findings showed mild pancytopenia with haemoglobin 9.6g/dL, mean corpuscular volume 102fL, leukopenia 2600 and 66000 platelets per cubic millimetre. Tests were all negative for HIV, syphilis and viral hepatitis, as for antinuclear antibodies. Folate and vitamin B12 were in the reference range.
Myelogram and bone marrow biopsy showed marked presence of myeloid blasts, suggesting acute myeloid leukaemia. The karyotype detected the translocation t(8;21)(q22;q22) with RUNX1-RUNX1T1, the most common fusion gene in acute myeloid leukaemia and associated to favourable outcomes.
Neutrophilic dermatosis of the hand is an inflammatory condition related to Sweet Syndrome. It often mimics infections with erythematous, violaceous inflammatory plaques that may ulcerate and commonly affects the dorsum of the hand . It is usually benign and idiopathic, but it might accompany systemic autoimmune disorders, infections, or hematopoietic malignancies such as acute leukaemias .
Therefore, recognising neutrophilic dermatosis should not be delayed, and the present case represents the need for an accurate diagnosis.