Histiocytoid neutrophilic dermatitis, an unusual histopathology in neonatal lupus erythematosus.

The authors reported histiocytoid neutrophilic dermatitis in neonatal lupus erythematosus (NLE). One-month-old male infant presented with annular erythematous plaques at the face and trunk. Serologic studies revealed positive anti-ribonuclear protein antibodies (RNP) and antinuclear antibodies (ANA). Histopathology showed predominant myeloid lineage mononuclear cells admixed with segmented neutrophils. This finding is uncommon in cutaneous NLE. Cutaneous NLE and LE should be included in the differential diagnosis of histiocytoid neutrophilic dermatitis. Additional immunohistochemistry studies with clinical and serologic correlations are important to differentiate histiocytoid neutrophilic dermatitis from the other diagnoses, especially leukemic cutis in young patients.