Enneking staging of malignant spinal tumors. Capsule of tumor is indicated by 1, pseudocapsule is indicated by 2, island of tumor within pseudocapsule (satellites) is indicated by 3 and at distance (skip metastases) is indicated by 4. Types IB and IIB tumors can compress cord if expanding posteriorly. Pseudocapsule is more or less infiltrated by neoplastic tissue, which can have direct contact with dural sac.