Headaches in brain tumor patients: Primary or secondary?

Background Headaches occur commonly in all patients, including those who have brain tumors. It has been argued that there is a classic "brain tumor headache type" - defined by the International Headache Society as one that is localized, progressive, worse in the morning, aggravated by coughing or bending forward, develops in temporal and often spatial relation to the neoplasm, and resolves within 7 days of surgical removal or treatment with corticosteroids. Methods Using the search terms "headache and brain tumors," "intracranial neoplasms and headache," and "facial pain and brain tumors," we reviewed the literature from the past 20 years on brain tumor-associated headache and reflected upon the International Classification of Headache Disorders-3 (ICHD-3). In a separate, complementary paper, the proposed mechanisms of brain tumor headache are reviewed. Results We discuss multiple clinical presentations of brain tumor headaches, present the ICHD-3 diagnostic criteria for each type of headache, and then apply our findings to the ICHD-3. Our primary and major finding was that brain tumor headaches can present similarly to primary headaches in those with a predisposition to headaches, suggesting that following ICHD-3 criteria could cause a clinician to overlook a headache caused by a brain tumor. We further find that some types of headaches are not explicitly discussed in the ICHD-3 and also propose that the International Headache Society formally define SMART (Stroke-like Migraine Attacks after Radiation Therapy) syndrome given the increasing amount of literature on this disorder. Conclusion Our literature review revealed that brain tumor headache uncommonly presents with classic brain tumor headache characteristics and often satisfies criteria for a primary headache category such as migraine or tension-type. Thus, clinicians may miss headaches due to brain tumors in following ICHD-3 criteria, and the distinction between primary and secondary headache disorders may not be so clear-cut.