Phimosis

Phimosis is the inability to retract the foreskin (prepuce) over the glans penis. It is classified as physiologic (normal developmental - present in 96% of newborns, resolving by age 3-5 through progressive keratinization and intermittent erections that naturally separate preputial adhesions) or pathologic (acquired fibrotic narrowing from scarring or inflammation). Physiologic phimosis results from natural epithelial adhesions between the inner prepuce and glans. During fetal development, the prepuce and glans are fused as a single epithelial sheet. Postnatal desquamation produces smegma (collections of shed epithelial cells and sebaceous secretions) that gradually separates the preputial space. By age 17, only 1% of males retain physiologic phimosis. Pathologic phimosis develops from chronic inflammation and fibrosis of the preputial tissue. The most important cause is lichen sclerosus (balanitis xerotica obliterans - BXO), an autoimmune chronic inflammatory dermatosis. At the molecular level, BXO involves T-lymphocyte (predominantly CD4+ and CD8+) infiltration of the dermal-epidermal junction, targeting basal keratinocytes through perforin/granzyme-mediated cytotoxicity and Fas/FasL apoptotic signaling. This leads to vacuolar degeneration of the basal layer, progressive basement membrane thickening (sclerosis), and upper dermal hyalinization with loss...