UNLABELLED: Measuring pressure ulcer outcomes for deep tissue injury (DTI) in pressure ulcers has improved the authors' understanding of DTI. The authors' multidisciplinary team has also identified previously unexplored patterns of tissue necrosis. OBJECTIVE: Illustrate these new patterns of tissue necrosis and report their incidence in a hospital setting. METHODS: Progressive tissue deterioration was explored using CT scans and ultrasonography of 326 Stage IV pressure ulcers with deep tissue injuries (DTI) managed by a multidisciplinary wound care team using standardized protocols of care in a Japanese hospital from June 2002 to June 2006. RESULTS: Two new patterns of pressure ulcer necrosis were found and are illustrated. All patients were checked consecutively and treated by the multidisciplinary team every 2 weeks. Among the consecutive sample of 326 patients, 194 (60%) were common DTI with column-shaped necrosis, including 7 with relatively healthy tissue sandwiched between shallow and deep necrosis. The remaining 132 (40%) had hourglass-shaped area of necrosis, including 20 with sandwiched-shaped necrosis. Hourglass shaped necrosis was associated with a combination of shear forces and pressure over a bony prominence. Sandwich-shaped hourglass necrosis often appeared to heal the superficial tissue but was reopened with deep necrosis that liquified and sloughed. CONCLUSION: Understanding the morphology and course of deterioration and healing of these different types of necrosis has helped the team recognize and manage previously unpredictable DTI, improving staff, patient, and family expectations, and reducing misunderstandings about pressure ulcer development.