Primary non-Hodgkin's lymphoma (NHL) of the skull with extra- and intracranial extension without systemic or skeletal manifestation in a non-immunocompromised patient is extremely rare. Up to date, only nine such cases have been reported in the literature and in none was the lesion located in the midline. The authors report a unique case of a primary NHL involving the midline of the cranium. The lesion presented as a slowly growing scalp swelling mimicking a parasagittal meningioma. The angiographic findings of mild vascularity in the periphery of the tumor and downward displacement of a patent superior sagittal sinus indicated that the lesion was unlikely to be a meningioma. Neurosurgeons must maintain a broad differential diagnosis in any patient with a scalp mass eroding through the skull and associated neurological symptoms or signs. An intraoperative frozen section is recommended since the identification of a lymphoma is likely to influence the neurosurgeon's decision about the extent of the surgical excision.