Two patients who had focal neurological deficits as the initial manifestation of a malignant non-Hodgkin's lymphoma involving the skull are described. Soft-tissue masses and variable bone destruction were the predominant computed tomographic findings, and magnetic resonance imaging studies revealed meningeal involvement in one case and sinus thrombosis in the other. Malignant non-Hodgkin's lymphomas initially appearing in the skull are rare, but these lesions should be considered in patients with a palpable scalp mass who have focal neurological signs.