Epidermoid Cyst of the Skull: A Case Highlighting Long-Term Evolution and Advanced Imaging Features

This study presents a congenital cranial epidermoid cyst with an unprecedented 70-year latency period, elucidating its distinct clinicoradiological features. A 72-year-old woman presented with a slowly enlarging, painless mass in the left frontoparietal region. Imaging revealed skull erosion, restricted diffusion on diffusion-weighted imaging, and hypoperfusion on perfusion-weighted imaging. Cinematic rendering was innovatively applied, providing three-dimensional visualization of intracystic cholesterol deposits and calcifications, which guided precise surgical excision (pathologically confirmed keratin debris). Key takeaways include identification of exceptionally prolonged latency (longest documented), advocating lifelong surveillance; demonstration of superiority of cinematic rendering in resolving complex internal architecture (e.g., solid-cystic interfaces, heterogeneous components), revolutionizing preoperative evaluation protocols; and establishment of a multimodal imaging signature (restricted diffusion + hypoperfusion + computed tomography density heterogeneity) strongly correlated with histologic constituents (keratin/calcifications), enhancing diagnostic specificity. This study provides novel evidence for personalized management and advanced imaging assessment of cranial epidermoid cysts.