Hematoma of Meckel’s cave: a rare possible symptomatic trigeminal neuralgia

According to the International Classification of Headache Disorders (2004), trigeminal neuralgia (TN) can be divided into classical and symptomatic [1]. The symptomatic TNs represent about 2% of cases and typically are caused by extrinsic lesions that produce neuropathy, demyelination, and axonopathy. We report on an unusual case of symptomatic TN due to an expansile lesion in the Meckel’s cave. A 54-year-old man presented with repetitive, severe stabbing pain localized to the left first and second trigeminal branch territory (zygomatic arch and orbit) lasting 1–2 min with a frequency of about 10–15 attacks/day. Despite that this symptomatology had developed abruptly, a dull background of persistent pain in the same region had started about 15 days before. The background pain was associated with photo-phonophobia and worsened with physical exertion. His past medical history was unremarkable. The patient did not present any cerebrovascular risk factors such as smoking, diabetes, or high blood pressure. The neurologic examination revealed an absence of the left corneal reflex and numbness in the ophthalmic and maxillary divisions of the nerve. A contrast-enhanced brain MRI detected an expansile lesion of the Meckel’s cave (Fig. 1a–d) with a cisternal portion and consequent dumbbell appearance. The lesion was T1-hyperintense on non-enhanced images and did not disappear on fat-saturated diffusion-weighted imaging, thus suggesting the presence of blood degradation products; after contrast medium administration, a marked enhancement of the cisternal portion of the trigeminal nerve was noted. Routine blood tests and hemocoagulative screening were normal; conventional catheter angiography of cerebroafferent vessels was negative. The patient underwent surgery that found a swollen and hemorrhagic Gasserian ganglion. At histology, blood without other pathologic tissue or microarteriovenous malformation was evidenced. After surgery, the pain resolved almost completely, while a complete left trigeminal deficit still persisted. At 3-year contrast-enhanced brain MRI, no sign of tumor was found in the Meckel’s cave, whereas a severe left masticatory muscles fatty degeneration was noted (Fig. 1d–f). Indeed, the patient presented with evident facial asymmetry due to severe left temporal and masseter muscle atrophy, without severe functional impairment. Traditionally, secondary TN constitutes a clinical syndrome attributed to a distinct, structural, pathologic lesion such as tumor, aneurysm, or other vascular malformation. The description of the pain can be identical to that seen in primary TN, with the exception that it tends to be accompanied by a continuous dull pain in the background and by trigeminal hypoesthesia or depression of the corneal reflex [2]. The age of onset may be somewhat younger than in the idiopathic cases, but it depends on the type of the structural lesion. We highlight an unusual cause of symptomatic TN related to an unknown-origin bleeding of the Gasserian ganglion mimicking a lesion. In the literature, only one case of spontaneous hematoma of Meckel’s cave has been reported [3]. A differential diagnosis needed to be performed with a hemorrhagic trigeminal schwannoma [4] or bleeding due to microarteriovenous malformation in the Meckel’s cave. Sometimes the latter might be F. Maggioni (&) M. Bellamio M. Margoni G. Zanchin Department of Neurosciences, Headache Centre, University of Padua, Via Giustiniani 5, 35128 Padua, Italy e-mail: ferdinando.maggioni@unipd.it