Leptomeningeal and intramedullary metastases of glioblastoma multiforme in a patient reoperated during adjuvant radiochemotherapy

Glioblastoma multiforme (GBM) is the most common primary malignancy of the central nervous system (CNS) in adults. Macroscopically evident and symptomatic spinal metastases occur rarely, in up to 2% to 5% of patients [1, 2]. Spread or dissemination within the neuraxis [3] is commoner than spread to other areas like the vertebral body and peritoneum which have also been reported [4, 5]. We present a rare case of symptomatic spinal leptomeningeal and intramedullary metastases of GBM in a patient who has been previously surgically treated with primary subtotal resection and underwent a repeated surgery during adjuvant radiotherapy and chemotherapy with temozolomide.

Gliomas comprise a heterogeneous group of tumours that differ in location within the CNS, in age and sex distribution, in morphological features, in tendency to progression, and in response to surgical and oncological treatment. GBM remains the most aggressive of gliomas, a collection of tumours developing from glial tissue or their precursors, accounting for 12% to 15% of all intracranial neoplasms [2]. First described by Rudolph Virchow in 1863, it represents the most common tumour of the cerebral hemispheres, usually occurring between the ages of 40 and 60 years old. Genetic alterations such as point mutations, loss of heterozygosity or excessive activation of a particular genes are all reported in GBMs, but intrinsic risk factors are currently unknown [6]. Evidence of association with occupational risk factors, head injury or exposure to electromagnetic fields is inconclusive. The incidence in Europe and North America is two to three cases/100,000 per year [7]. However, much less commonly, GBM can affect the brainstem (especially in children) and the spinal cord [8, 9]. Clinically, gliomas are divided into four grades; the most aggressive of these, grade IV or GBM, is also the most common in humans. These tumours may develop from lower-grade astrocytomas (WHO grade II) or anaplastic astrocytomas (WHO grade III) (secondary GBM), but more frequently they manifest de novo, without any evidence of less malignant precursors (primary GBM) [10, 11]. They all typically contain both neoplastic and stromal cells, which contribute to their heterogeneity and variable outcome. Molecular studies and gene profiling potentially allow for better classification of these tumours and their division into different prognostic groups.

With the exception of brainstem gliomas, GBM has the worst prognosis of any CNS malignancy, despite multimodality treatment. The current standard of care for glioblastoma is surgical resection of as much of the tumour as is safe and possible, followed by postoperative radiation therapy (focal irradiation at a dose of 2 Gy/fraction given once daily 5 days per week over a period of 6 weeks, for a total dose of 60 Gy) and chemotherapy (temozolomide at a dose of 75 mg/m²/day, given 7 days per week from the first day of radiotherapy up to the last day of radiotherapy, but for no longer than 49 days). After a 4-week break, patients were then to receive up to six cycles of temozolomide according to the standard 5-day schedule every 28 days. [12]. To date, systemic delivery of different chemotherapeutic agents to GBM has had limited efficiency with significant side effects including haematological toxicity, specifically thrombocytopenia and neutropenia. Even under the best of circumstances, where all of the tumour seen on MRI scan can be surgically removed and patients are fully treated with radiochemotherapy, over 75% of patients die within 18 months and essentially none attain long-term survival [13, 14]. However, some progress is being made in the field of molecular neuro-oncology, which involves an understanding of the mutations and expression of genes that have been implicated with GMB pathophysiology [15, 16, 17, 18, 19, 20, 21, 22, 23]. Such procedures may be helpful to identify the tumour and they also could facilitate therapy as potential vectors of treatment [24, 25]. The main objective is not only to generate more new drugs; it is also to find different tools to assault specific types of different brain tumours. Finally, a genetic profile could be the deciding factor in the diagnosis and treatment for each patient individually, while best meeting cost/benefit issues.

Notwithstanding all this, the treatment of GBM still remains one of the most disappointing challenges in modern oncology. A surgical cure for these brain tumours is virtually impossible to provide. The clinical course is determined by the biology of the tumour and response to surgery, radiation and chemotherapy [26]. In our patient, the treatment was multimodal and multidisciplinary, based on cytoreductive surgery followed by chemotherapy (temozolomide) and radiotherapy. As we know, surgical intervention and radical resection are essential in the initial treatment while the extent of surgery can affect overall patient survival [27, 28, 29, 30]. When faced with evidence of recurrent or metastatic GBM, surgical intervention requires identification of goals and a clear consideration of overall prognosis, including all treatment side effects. In patients with good KPS (>70) and without significant contraindications, surgery can improve neurological status and reduce intracranial pressure. Repeated resection should only be considered in patients with high preoperative KPS (>70) or in those whose symptoms are secondary to mass effect from superficial regions and whose lesions are in a favourable brain location [30]. Radiological follow-up should include brain/spinal MRI every 4 to 6 months after the cranial removal [31]. However, the efficacy of repeated resection alone in cases of recurrent GBM remains controversial due to a lack of randomized clinical trials. Some studies showed that the median survival time after resection was 14 to 50 weeks [32, 33, 34].

As mentioned earlier, spinal or systemic GBM metastases are very rare [1, 2]. This could be because of patient death before clinically detectable spreading or impediments to systemic egress. Spinal and dural metastases should be commonly suspected in all patients with a history of intracranial GBM who complain about signs and symptoms not explained by the primary lesion. The clinical diagnosis of these conditions may be difficult, but is possible with careful neurological examination directed at radicular signs. Spinal MRI with contrast enhancement has a leading diagnostic role in patients with serious spinal pathology and should be considered in the presence of any clinical signs of spinal involvement [35, 36]. To date, the cause of the tumour spread still remains under discussion. It probably develops at the time of intracranial progression following a surgical procedure. According to other hypothesis, spinal metastases most likely occur as a result of cellular spread in the subarachnoidal space or haematogenous dissemination [2]. Any new onset of axial back pain or neurological deficit of the extremities in patients with prior diagnosis of GBM should indicate suspected spinal metastasis, however rarely they may occur.

The prognosis in cases of leptomeningeal metastasis is very poor, regardless of the treatment modality used. The survival of patients is approximately 2 to 3 months [37, 38]. Radiotherapy is the most common treatment modality with 3 to 4 Gy per fraction to a total dose of up to 40 Gy [39]. Radiotherapy may provide relief of pain and some improvement in neurological function, but no survival benefits. Systemic chemotherapy or intraventricular chemotherapy in combination with radiotherapy has also not improved overall survival [40]. Surgery may enhance the risk of drop metastases, although these have also been reported in patients who have never had a surgical procedure [41].

Although merely a theoretical possibility in most cases, reoperation of GBM during adjuvant radiochemotherapy was still feasible in our patient. Today, the main objective of chemoradiotherapy in patients with metastatic GBM is to prevent neurologic deterioration and improve health-related quality of life [26]. Researchers continue to study the common characteristics of GBM and how personalized and targeted treatments may be optimally used. With this paper, we not only aim to present this rare entity, but also to emphasise the importance of a multidisciplinary approach, a key function in the management of tumour patients. Additionally, clinicians should be familiar with the possibility of extracranial spreading of GBM because as treatment improvements provide better control of the primary tumour and improving survival, metastatic disease will be increasingly encountered.

Written informed consent was obtained from the patient to the publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.