- It is divided into three grades, depending on the degree of necrosis and cellular atypia. The grades of disease are histologically-based and do not necessarily correlate with clinical outcome. However, like other EBV related LPD's, LYG can transform into an aggressive large B-cell lymphoma, which would be included within the grade 3 category. It is important to note that not all grade 3 lesions are a large B-cell lymphoma.