Recurrent secondary milia after full-thickness skin graft using retroauricular donor skin for dog-bite defect: a case report.

Full-thickness skin grafting (FTSG) is frequently used to reconstruct facial soft tissue defects because it provides favorable color and texture matching. Secondary cystic lesions, including milia or epidermal cysts, that develop after FTSG are rare. A 29-year-old woman sustained a dog-bite injury resulting in a 4.5× 2.5 cm defect involving the philtrum and upper lip. The philtrum was reconstructed using a full-thickness skin graft harvested from the retroauricular area, while the upper lip was repaired using a mucosal V-Y advancement flap. Ten months later, hypertrophic scarring developed, and a second FTSG was performed using contralateral retroauricular skin. Despite repeated intralesional triamcinolone injections, the grafted area became tender and pruritic, with the appearance of multiple milia-like lesions. Over the subsequent 9 months, three recurrent cystic nodules developed within the scar tissue and were serially excised. Histopathological examination confirmed the diagnosis of secondary milia. After complete excision, no recurrence was observed for over 3 years. We discuss possible contributing mechanisms, including adnexal survival within grafts and the role of remnant epidermis or ductal obstruction. Awareness of this complication may help guide donor-site selection and wound-bed preparation in perioral reconstruction.