Idiopathic Mixed Neutrophilic Panniculitis of the Eyelid: An Unusual Finding

Panniculitis is an inflammatory condition typically presenting with painful, erythematous subcutaneous nodules on the extremities, often linked to systemic diseases such as lupus or erythema nodosum. Eyelid involvement is rare and has not been previously reported as an isolated finding. The authors report the case of a 74-year-old woman referred with presumed preseptal cellulitis secondary to a stye. Clinical signs included conjunctival chemosis, malar edema, and a firm, deep-seated mass in the inferolateral right lower eyelid. Orbital MRI revealed a well-defined lesion with homogeneous enhancement and surrounding inflammation. An excisional biopsy showed mature adipose tissue infiltrated by a polymorphous inflammatory cell population, predominantly neutrophils and eosinophils. Immunohistochemistry revealed a CD4>CD8 T-cell predominance. The lesion was diagnosed as idiopathic mixed neutrophilic panniculitis with no evidence of vasculitis or malignancy. This case represents the first report of isolated eyelid panniculitis, expanding the differential diagnosis of periocular inflammatory lesions.