Particular attention is given to the high incidence of cerebral lymphomas associated with adult CNH. Intracerebral B-cell lymphoma represents less than 1% of all primary malignant tumors of the central nervous system. Infiltration of lymphoma cells into the pons and medulla is the most frequently reported cause of CNH, accounting for half of all CNH-inducing brain tumors, despite its considerable rarity. It has been suggested that these lymphomas are capable of diffusely penetrating the midbrain, without significantly destructing the overall structures.