Keep CALME (childhood asymmetry labium majus enlargement) and follow up.

CALME is the abbreviation of "childhood asymmetry labium majus enlargement" and denotes a physiological, non-neoplastic swelling of labium majus soft tissues. It is caused by the expansion of one or more normal vulvar tissue components and is devoid of a peripheral capsule. A few reports in the literature have raised awareness of this benign condition and stressed the need to avoid invasive procedures with possible permanent sequelae. The etiopathogenesis of CALME is still debated, although the hypothesis of a hormone-driven major labia stromal hyperplasia is favored over the assumption of a benign neoplastic process. This article aims to provide a detailed review of the clinical, histological, and instrumental findings of CALME and provide a step-based algorithm to approach and manage genito-inguinal masses in pediatric patients.