This classification represents a project aimed at bringing together the variety of ways thymic epithelial neoplasms have been classified. It focuses on their growth characteristics, and cytoarchitectural features . The classification, though restricted to the thymic region rather than the mediastinum in general, also covers neuroendocrine, germ cell, lymphoid, and stromal tumours, as well as tumour-like lesions and the neck tumours of thymic or related branchial pouch derivation.