Primary bone lymphoma (PBL) is a relatively uncommon entity. However, involvement of the cranial vault is an unusual manifestation of aggressive non-Hodgkin's lymphoma. We report the case of a 42-year old immunocompetent woman who presented with an enlarging mass involving the right parietal bone. Magnetic resonance imaging (MRI) of the brain revealed an expansive tumor that affects the right parietal bone. Computed tomographic (CT) scans of the abdomen, chest and pelvis were negative for lymphadenopathy or organomegaly. Biopsy of the mass showed diffuse large B-cell non-Hodgkin's lymphoma confirmed by immunohistochemical study. The patient had a complete response after 4 cycles of chemotherapy followed by external beam radiotherapy. After a follow-up of more than 9 months the patient is still in good local control without distant metastasis. The aim of our work is to report a case of Primary bone lymphoma of the cranial vault with good response to treatment combining sequential chemotherapy and radiotherapy.