Frans-Jan H. Hulsmans

Primary nerve-sheath tumours of the trigeminal nerve: clinical and MRI findings

Abstract We reviewed the clinical and MRI findings in primary nerve-sheath tumours of the trigeminal nerve. We retrospectively reviewed the medical records, imaging and histological specimens of 10 patients with 11 primary tumours of the trigeminal nerve. We assessed whether tumour site, size, morphology or signal characteristics were related to symptoms and signs or histological findings. Histological proof was available for 8 of 11 tumours: six schwannomas and two plexiform neurofibromas. The other three tumours were thought to be schwannomas, because they were present in patients with neurofibromatosis type 2 and followed the course of the trigeminal nerve. Uncommon MRI appearances were observed in three schwannomas and included a large intratumoral haemorrhage, a mainly low-signal appearance on T2-weighted images and a rim-enhancing, multicystic appearance. Only four of nine schwannomas caused trigeminal nerve symptoms, including two with large cystic components, one haemorrhagic and one solid tumor. Of the five schwannomas which did not cause any trigeminal nerve symptoms, two were large. Only one of the plexiform neurofibromas caused trigeminal nerve symptoms. Additional neurological symptoms and signs, not related to the trigeminal nerve, could be attributed to the location of the tumour in three patients.

Perineural tumor extension along the trigeminal nerve: magnetic resonance imaging findings

OBJECTIVE To evaluate the magnetic resonance imaging (MRI) findings of 15 patients with perineural tumor extension along the trigeminal nerve in correlation with clinical data. METHODS The clinical records and MRI studies of 15 patients with perineural tumor extension along the trigeminal nerve were retrospectively reviewed. Imaging studies included plain and contrast-enhanced thin section T1-weighted spin echo (T1-WSE) MRI with and without fat-suppression. The studies were compared to determine which sequence provided greatest tumor conspicuity and best depiction of tumor extent. The conspicuity of these tumors was assessed on the available sequences by two observers by consensus. RESULTS The contrast-enhanced T1-weighted spin echo fat-suppressed images (T1-WSECEFS) demonstrated greatest tumor conspicuity and best depiction of tumor extent in the extracranial head and neck and skull base region. The conventional T1-weighted spin echo pre- and postcontrast images were, however, diagnostic of perineural tumor extension in 11 patients due to the presence of considerable tumor bulk and extension well above the skull base. In the other four patients the perineural tumor was poorly visualized on the conventional T1-WSE images and well visualized on the fat-suppressed images. The mandibular division of the trigeminal nerve (V3) was most commonly involved (n = 10), followed by the maxillary (V2; n = 5) and ophthalmic (V1; n = 2) division. Two patients had both mandibular as well as maxillary nerve involvement. The finding of perineural tumor extension had significant impact on patient management: based on the MR imaging study, the primary tumor was considered inoperable (n = 13), the extent of surgery was expanded (n = 2) and radiation therapy (RT) ports were extended (n = 12). CONCLUSION Complete trigeminal nerve imaging is recommended when evaluating (suspected) head and neck malignancies with a high risk for perineural extension. In these cases thin section axial and coronal precontrast T1-WSE MR images and postcontrast T1-WSE MR images with fat-suppression should be obtained. In the rare event that artifacts degrade the quality of the fat-suppressed images, contrast-enhanced T1-WSE sequences without fat-suppression can additionally be used.

Perineural tumor extension of facial malignant melanoma: CT and MRI.

A case of retrograde perineural tumor that spread from malignant melanoma of the face is reported. Contrast-enhanced CT and plain and contrast-enhanced MR studies, including fat suppression technique, showed tumor extension along the maxillary division of the trigeminal nerve. Histopathological examination of the surgical specimen revealed neurotropic malignant melanoma and confirmed the extent of tumor spread in the perineurium.

The use of CT-angiography for monitoring thrombus formation after balloon occlusion of a dissecting vertebral artery pseudoaneurysm

We present a 49-year-old man with a subarachnoid haemorrhage from a dissecting vertebral artery (VA) pseudoaneurysm treated with a proximal balloon occlusion. The clinical course was complicated by the sudden appearance of a lateral medullary syndrome (Wallenberg), which completely resolved after anticoagulant therapy. During this course, CT-angiography (CTA) enabled monitoring of both the progression and partial resolution of the thrombus in the occluded VA. An anatomical variant of a perforating artery originating from the VA proximal to the posterior inferior cerebral artery (PICA) was subsequently demonstrated, explaining the ischemic event. The value of CTA in clinical management is discussed. The prophylactic use of anticoagulant therapy especially in the case of a perforating artery to the lateral medulla originating proximally to the PICA, is suggested.