Precursor T-cell Lymphoblastic Lymphoma is a neoplasm of childhood and young adolescence with a male predominance. But it may also occur in adults as in this 30 y/o male who presented with an anterior mediastinal mass. Sections showed diffuse sheets of small to intermediate sized cells. The tumor cells were positive for CD3, CD43, & TdT. They were negative for CD20, CD34, kappa, lambda, and cytokeratin.