Facial Retaining Ligaments Influence Basal Cell Carcinoma Growth in the Midface and Periorbital Region

ABSTRACT Objectives Facial retaining ligaments (RLs) are well‐characterized for their role in soft‐tissue support and in rhytidectomy. This study investigates whether RLs also act as anatomical barriers that influence the spread of basal cell carcinoma (BCC). We hypothesized that the dermal insertion of RLs impedes the dermal spread pattern of BCCs, specifically causing them to grow along the RL. Methods We conducted a retrospective cohort study of 163 patients who underwent Mohs micrographic surgery (MMS) for BCC. Post‐MMS defects were used as a proxy for the BCC size and shape. The defects were categorized as “near,” “far,” or “crossing” based on their proximity to the RL. Defect symmetry was quantified using the perpendicular‐to‐parallel ratio of the defect relative to the RL. A relative proximity ratio (RPR) was used for continuous linear regression analysis. Results Analysis revealed significant defect asymmetry in lesions near RLs. The “near” group demonstrated a growth pattern parallel to the RL (ratio of 0.73) compared to the “far” group (ratio of 0.98, p < 0.0001). Linear regression confirmed that RPR was a predictor of tumor growth parallel to the RL ( B = 0.099, p < 0.0001). Only 5.5% of lesions breached the RL. Conclusion RLs correlate with an eccentric, oblong BCC growth pattern parallel to the direction of the ligament. Recognizing lesions within these zones may improve preoperative counseling and reconstructive planning. Level of Evidence III.