Cluster headache as a manifestation of intracranial inflammatory myofibroblastic tumour: a case report with pathophysiological considerations.

We report a patient with a secondary form of chronic cluster headache, caused by an intracranial presentation of inflammatory myofibroblastic pseudotumour located in the posterior fossa, with total remission of the pain after resection. The headaches were resistant to many of the usual treatments for cluster headache. The patient had two normal computed tomography scans and one normal magnetic resonance imaging of the head before the additional diagnosis of brain tumour was made. This is an unusual cause of cluster headache with intracranial mass, with an unexpected clinical presentation, a rare triggering manoeuvre, unusual pathology and successful treatment. This patient probably had the hypothalamic biological predisposition to cluster headache and, when a small mass disturbed pain-sensitive structures in the posterior fossa, it excited the trigeminovascular system via posterior fossa trigeminal and upper cervical afferents, and triggered the pathophysiological processes that resulted in a secondary form of chronic cluster headache.