Neuroradiolegv

Neuroradiology (1985) 27:426-429

© Springer-Veflag 1985

Bony metastases from malignant intra-cranial astrocytoma V. P. L. Hornsby Department of Radiology, Hull Royal Infirmary, Anlaby Road, Hull, Yorkshire, England

Summary. Extra-cranial skeletal metastases from primary intra-cranial gliomas are very rare. A case is reported of a patient who developed widespread skeletal deposits fifteen months after the excision of a cystic frontal astrocytoma.

Key words: Astrocytoma - bony metastases

mour. There was no tumour necrosis nor endothelial proliferation, but the vascular patterns, the significant cellular changes and the appearance of mitotic figures placed the tumour as an astrocytoma showing malignant change. The appearances at the centre of the tumour were so marked as to place it in the glioblastoma group. With radiotherapy she remained well for almost a year. In August 1982 she presented with pain in the thoracic spine and difficulty in emptying the bladder.

Case report A 35-year-old housewife presented to the neurology department of Hull Royal Infirmary in September 1981 with a one-month history of headaches and nausea and a very short history of diplopia. She was found to have a right-sided sixth nerve palsy and a CT Scan (Fig.l) showed a large cyst-like probably non-enhancing lesion in the right frontal region causing marked displacement of the anterior horns of the lateral ventricles to the left. The features suggested a cystic astrocytoma. Carotid angiography showed no evidence of malignant circulation: a radio-isotope brain scan revealed increased uptake in the right frontal region. The cystic tumour, which contained clear yellow fluid, was removed by lobectomy on 28 September by Mr. Gordon Brocklehurst. Microscopically (Figs. 5 and 6) the tumour was cellular and very vascular showing the features of an astrocytoma with microcyst formation at the periphery. Towards the centre of the tumour, the cellularity was greatly increased, together with bunches of small vessels and transformation to gemistiocytes. There was marked cellular pleomorphism with occasional giant and ring-type cells. Mitotic figures were present in small numbers, particularly in the central area of the tu-

Fig. 1. CT Scan, September 1981. Cystic Astrocytoma Right Fron-

tal Lobe Fig. 2. Myelogram, August 1982, showing extradural block at the level of T6 and destruction of the pedicle of T6

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Fig.3. Chest radiograph in January 1983, shortly before death, showing lytic destruction of the left 7th and 8th ribs posteriorly Fig.4. A.P. Pelvis and Hips, January 1983, showing widespread lytic metastases in pelvis and upper femora

A Myelogram showed extradural cord compression at the T6 level (Fig. 2) and the body of T6 was noted to have an abnormal trabecular pattern. An emergency decompression laminectomy was performed and an extradural metastasis involving the bodies of T5 and T6 and the right pedicle of T6 incompletely removed. The histology of the tumour (Figs. 7 and 8) was similar to the glioblastoma removed in 1981. Post-operative radiotherapy was given to the spine but unfortunately the patient became totally paraplegic. Radiographs of her chest and pelvis shortly before her death in January 1983 showed widespread lytic metastases (Figs. 3 and 4).

Discussion

It is rare for malignant astrocytoma or glioblastoma to metastasise to bone; local recurrence of the tumour at the site of primary excision is common and it may invade bone. Subarachnoid seeding of the tumour is a less likely event. A French team from Grenoble [1], in a review of the world literature in 1980, documented 73 histologically proven cases of astrocytoma or glioblastoma with extraneural metastases. Of these 73 cases, 20 metastasised to bone (27%). In 1969, Smith et al. [2] reported a series of 8000 primary neuro-ectodermal tumours, 35 of which metastasised, and these included 23 glioblastomas; one can expect, therefore, approximately 0.4% of primary neuroectodermal tumours to metastasise, and of those which do, approximately 66% will be glioblastomas.

Extraneural metastases, however, do not appear to affect survival time adversely. Survival time in the Grenoble study suggested that 82.8% of patients with extraneural metastases died within 2 years, whereas 90% of patients with glioblastomas and without remote metastases died within 2 years [3]. The average time of survival of patients treated with excision and radiotherapy in the Grenoble series was 23.3 months; our patient survived 16 months. Why do glioblastomas metastasise extraneurally so seldom? It is perhaps surprising in view of the fact that experimental work has shown that malignant glial cells will grow freely in unfamiliar surroundings [4, 5]. Moreover, most glioblastomas are highly vascular tumours and the blood/brain barrier is breached; there is, therefore, no effective barrier to the passage of malignant glial cells into the general circulation and to the formation of widely disseminated micrometastases. It has been suggested that dissemination might actually be encouraged by the negative intra-vascular pressure within opened venous sinuses during the operation and subsequent aspiration of tumour cells into the blood stream [6], the arguments against this hypothesis are firstly that there is no effective blood/ brain barrier in gliomas even before venous sinuses are opened, and secondly tumours which have not been operated upon have metastasised [7]. A more plausible explanation is that the growth of extracranial metastases is principally governed by the relationship between the glial micrometastases and the environment in which they find themselves [81 (a host/tumour relationship) and by the effectiveness of the patient's own immuno-surveillance.

Fig.5. Primary tumour ( x 8) showing giant cells and the vascular pattern of the glioblastoma

Fig. 6. Primary glioblastoma ( x 20) showing giant cells and an atypical mitotic figure

Fig. 7. Metastatic tumour in marrow cavity of spine ( × 20)

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Fig. 8. Metastatic glioblastoma in extradural spinal connective tissue ( x 20)

Acknowledgements. The author would like to thank Mr. Gordon Brocklehurst (Consultant Neurosurgeon) and Dr. A.E.Pratt (Consultant Radiologist) for permission to report this case and for their helpful comments; the Medical Illustration Department for preparing the prints and Miss Christine Whatling for typing the manuscript.

References 1. Pasquier B, Pasquier D, Golet AN, Meng Hong Panh and Couderc P (1980) Extraneural metastases of astrocytomas and glioblastomas. Cancer 45: 112-125 2. Smith DR, Hardman JN, Earle KM (1969) Metastasising neuroectodermal tumours of the central nervous system. J Neurosurg 31 : 50-58 3. Rubenstein LJ (1972) Tumours of the central nervous system. Atlas of Tumour Pathology, Ser 2, Fasc. 6, Armed Forces Institute of Pathology, Washington DC 4. Lumb G (1954) Transplantation of human brain tumours into mouse brain. Br J Cancer 8: 434-444

5. Battista AF, Bloom W, Loffman M, Feigin I (1961) Autotransplantation of anaplastic astrocytoma in the subcutaneous tissues of man. Neurology 11:997-981 6. AbbottKH, LoveJG (1943) Metastasising intra-cranial tumours. Ann Surg 118:343-352 7. Anzil AP (1970) Glioblastoma multiform with extracranial metastases in the absence of previous craniotomy. J Neurosurg 33: 88 8. Hitchcock MH, Hollinshead AD, Chretien P, Rizzoli HVI (1977) Controlled testing for cell-mediated immune response in a long surviving glioblastoma multiforme patient. Cancer 40: 600-678 Received: 8 May 1984 Dr. V. P. L. Hornsby Department of Radiology Hull Royal Infirmary Anlaby Road Hull Yorkshire England