To the Editor: I read with great interest the report by Le and Burgoyne of a 64-year-old woman with painless unilateral lower eyelid fullness that developed three years after malar hyaluronic acid filler injection.The authors correctly identified a delayed filler-related complication, supported by the intraoperative gelatinous material, acellular foreign material on histopathology, the subsequently disclosed history, and improvement after hyaluronidase. 1 I wish to complement their discussion by highlighting four relevant infiltrative mimics.First, sarcoidosis may involve the eyelids, lacrimal gland, extraocular muscles, and orbital tissues.Eyelid granulomas, dacryoadenitis, uveitis, or proptosis may provide diagnostic clues.A compatible biopsy supports definite ocular sarcoidosis, whereas bilateral hilar adenopathy may support a presumed diagnosis.2 In this case, the normal ocular examination and absence of granulomas or an inflammatory infiltrate made sarcoid involvement unlikely.Second, the diagnostic criteria for IgG4-related ophthalmic disease integrate imaging, histopathology, and serum IgG4 concentration.Imaging may show enlargement of the lacrimal gland, trigeminal nerve, or extraocular muscles, as well as masses involving other ophthalmic tissues.Histopathology typically demonstrates marked lymphocytic and plasmacytic infiltration, sometimes with fibrosis, and abundant IgG4-positive plasma cells; serology alone does not establish a definite diagnosis.3 Isolated lower eyelid involvement, normal ocular motility, and the absence of an inflammatory infiltrate did not favor this diagnosis.Third, ocular adnexal lymphoma may involve the orbit, conjunctiva, lacrimal apparatus, or eyelid.In the series by Boltezar et al., 4 the median age was 68 years, and mucosa-associated lymphoid tissue lymphoma accounted for 71.6% of cases.Ocular adnexal lymphoma may manifest as an eyelid mass, ptosis, or painless proptosis; on imaging, an orbital mass typically is poorly defined and molds to adjacent structures without bony erosion.Diagnosis requires biopsy with histopathologic, immunophenotypic, and molecular studies.The absence of malignancy and the presence of acellular material did not support this diagnosis. Delayed Eyelid Masses: When to Suspect Infiltrative Mimickers