Sequential Dermoscopic, Histopathologic, and Immunopathologic Documentation of Regressing Seborrheic Keratosis: A Multimodal, Time‐Resolved Visual Case Study

Seborrheic keratosis (SK) typically shows stable behavior, and spontaneous regression is rarely documented. We report a unique case of SK that underwent complete involution within 8 weeks. Sequential clinical and dermoscopic imaging demonstrated a transition from classical SK structures to red‐blue homogeneous areas and, ultimately, to whitish regression zones. Histopathology revealed interface inflammation, keratinocyte degeneration, and epidermal remodeling. Immunohistochemistry confirmed a stepwise regression mechanism involving CD8 + /TIA‐1 + cytotoxic T‐cell activation, cleaved caspase‐3–mediated apoptosis, and keratinocyte‐derived amyloid deposition. To our knowledge, this is the first case to demonstrate a fully time‐resolved clinicodermoscopic‐immunopathologic sequence of cytotoxic regression in SK.