Imaging review of the anterior skull base.

The anterior skull base (ASB) is intimately associated with the unique soft tissue subtypes of the nasal cavity, paranasal sinuses, orbits, and intracranial compartment. Pathology involving the ASB is rare but the causes are manifold and can be broadly subdivided into those intrinsic to the skull base and processes extending from below or above. Sinonasal pathology is the most commonly encountered and poses significant management challenges that rely heavily on accurate interpretation of the radiological findings. We illustrate the normal anatomy of the ASB and present a cross-sectional imaging review of the pathological entities that may be encountered, focusing on the specific features that will impact on clinical and surgical management.

Skull base and craniocervical bone pneumatisation: two case reports of differing presentations and a review of the literature.

We report two patients with increased central skull base and craniocervical junction bone pneumatisation complicated by extra-osseous gas. One patient presented with symptoms of increasing nasal blockage and 'sinus pressure' on a background of extensive nasal polyposis. He was subsequently found to have a history of repeated Valsalva's manoeuvre, the cessation of which resulted in a rapid decrease in the amount of extra-osseous gas on imaging. The second patient presented following a minor head trauma with dysarthria from a hypoglossal nerve palsy and neck pain, with extensive intra- and extra-cranial gas including within the spinal canal (pneumorrhachis). These radiological findings have been reported previously in patients with Eustachian tube dysfunction and/or activities leading to frequently raised middle ear pressures. We review the possible aetiologies, reported risk factors, and the range of associated imaging abnormalities that may be encountered with this rare appearance.

Pulmonary lobar torsion: a rare complication following pulmonary resection, but one not to miss.

Lobar torsion is an uncommon phenomenon but a crucial diagnosis to consider in any patient undergoing lobectomy, as the clinical findings and radiographic appearances are non-specific. This case report documents the clinical and radiological evolution of middle lobe torsion in a patient who underwent right upper lobectomy for Stage 1 adenocarcinoma of the lung. The diagnosis of lobar torsion is most often made on CT scanning of the chest, which is frequently performed in order to distinguish this from multiple other more frequently encountered post-operative complications. Contrast-enhanced CT scan is the recommended imaging modality in suspected cases. If features of lobar torsion are identified, the findings must be communicated immediately to cardiothoracic surgeons owing to the potentially life-threatening consequences of delay. Management of lobar torsion is predominantly surgical, with several techniques currently in use; however, video-assisted thoracoscopic surgery is emerging as an increasingly favoured approach.

Pineal and leptomeningeal metastases from a parotid carcinoma ex pleomorphic adenoma.

Carcinoma ex pleomorphic adenoma (CEPA) is an uncommon complication of an untreated pleomorphic adenoma (PA), but one that has a life-threatening significance. This case report documents the clinical, radiological and histopathological features of an extremely rare case of biopsy-proven pineal metastasis, with cerebellopontine and leptomeningeal spread, from CEPA of the parotid gland in spite of the patient having undergone parotidectomy, ipsilateral neck dissection and adjuvant radiotherapy. In spite of the current surgical and oncological treatment of CEPA, the rates of recurrence and distant metastases are high, with a subsequently poor prognostic outcome in most patients. Distant spread is usually to the bones and the lungs; however, more unusual locations have been documented. Our finding of pineal metastasis from CEPA has not previously been reported in the literature. Although this is a rare complication of an unusual condition, the aggressive behaviour of these malignancies warrants close clinical follow-up, with a low threshold for re-imaging and investigation if indicated.