Clinical History
A 67-year-old woman presented with a soft non-tender left cervical swelling, evident for some months. She had a relevant past history of left sided Grade I cerebellopontine angle meningioma, partially resected 12 years earlier and which had remained stable on follow-up imaging, and chronic lymphatic leukaemia (Binet Stage A).
Imaging Findings
Neck ultrasound revealed a heterogeneous mass distending the left internal jugular vein with associated flow on Doppler examination (Fig. 1a-c). Post-contrast CT confirmed the intra-luminal location of this mass, with only a small rim of contrast between it and the vessel wall (Fig. 2a). Small enhancing vessels were seen within the mass (Fig. 2b). At the skull base, a large enhancing mass was noted at the left petrous apex, the site of the known residual meningioma (Fig 2c). Pre- and post-gadolinium MRI sequences demonstrated that the internal jugular vein mass was low signal on T1 and high signal on STIR sequences, enhancing homogeneously post-contrast (Fig. 3a-d). The left cerebellopontine angle extra-axial mass extended into surrounding structures (including the left jugular foramen and clivus), enhanced uniformly and had a dural tail (Fig. 4a-f). Ultrasound guided fine needle aspiration of the jugular vein mass confirmed intravenous extension of the skull base meningioma.
Discussion
Meningiomas arise from arachnoid cap cells in the meningeal coverings of the spinal cord and brain [1]. They are the most frequently diagnosed primary central nervous system tumour in adults, accounting for up to a third of these tumours [2, 3]. Meningiomas are classified according to the World Health Organisation (WHO) grading system as Grade I-III, recently updated in 2007 [1]. 80-90% of tumours are Grade I and, although defined as benign, show significant intra-class heterogeneity with recurrence rates of 7-25%.
Extracranial presentation of meningioma is uncommon and may occur with direct extension (most commonly), metastasis or primary extracranial meningioma. Direct extension into internal jugular vein, although much less common than involvement of the dura, adjacent venous sinuses and jugular foramen, has been described in a small number of case reports with implications for further management [4-6].
Seminal data collected by Simpson in the 1950s showed a clear correlation between completeness of surgical resection and 10-year recurrence rates, with subtotal resection corresponding to a 4-fold greater risk of recurrence compared with complete resection [7]. However, an important recent study has reported minimal differences in recurrence free survival when comparing aggressive with more conservative surgical approaches in the context of Grade I tumours, likely reflecting improvements in surgical technique [8]. Clearly, there is a compromise between complete excision, risk of recurrence/progression and functional outcomes and this is influenced by the precise anatomical location of the tumour. Even within the subcategory of cerebellopontine angle meningioma a representative study reports complete resection rates ranging from 100%-73% with functional preservation of the facial nerve ranging from 93%-73% [9].
Despite the revised WHO meningioma grading, aggressive behaviour is difficult to predict and there is a need for radiological parameters predictive of clinical outcomes. Whilst magnetic resonance (MR) is the most useful imaging modality in meningioma assessment, standard sequences do not readily differentiate benign and non-benign tumours. Furthermore, recent multivariate analysis of general tumour parameters on MR (including tumour size, location, associated calcification and oedema, brain-tumour interface and pial-cortical blood supply) found that only residual tumour volume ≥3cm3 was predictive of regrowth in residual Grade I tumours [10]. However, functional MR parameters with or without positron emission tomography (PET) are being correlated with clinical parameters and grade in some studies and, although still controversial, are likely to significantly impact on surgical and radiological management in the future [11].
Differential Diagnosis List
Internal jugular vein extension of Grade I cerebellopontine angle meningioma.
Schwannoma
Glomus jugulare tumour
Intravascular capillary endothelial hyperplasia
Angiosarcoma
Final Diagnosis
Internal jugular vein extension of Grade I cerebellopontine angle meningioma.