Brain Pathology Case of the Month - December 2003

DIAGNOSIS:      RECURRENT MENINGIOMA WITH RHABDOMYOSARCOMATOUS DIFFERENTIATION

DISCUSSION:

The presence of rhabdomyoblasts in central nervous system tumours is a well recognised but rare occurrence (e.g. (2), reviewed in (8)). When it does occur, the rhabdomyoblasts may be either the principle neoplastic cell (i.e. primary intracranial rhabdomyosarcoma) or they can be mixed with neuroglial cells (e.g. medullomyoblastoma, triton tumours and gliomyosarcoma). Our patient's case differs from both these groups of tumours as the rhabdomyoblasts are mixed with meningothelial cells.

There is one case report of a tumour that has some features in common with ours. Ferracini et al. (4) described a meningeal tumour composed almost entirely of rhabdomyoblasts. On retrospective analysis of all slides from this tumour, they found some areas with a meningothelial appearance on haematoxylin and eosin staining. These cells showed weak immunostaining for epithelial membrane antigen (EMA) consistent with meningothelial cells. They suggested that their tumour arose from a common precursor cell for meningothelial and muscle cells. However, in an accompanying commentary, Burger suggested that the areas of meningothelial whorls were in fact vascular (3). In contrast our patient's tumour consists of unambiguous meningothelial cells and rhabdomyoblasts based on morphological, immunohistochemical and ultrastructural grounds. Our case also differs as we found the rhabdomyoblasts developed in the recurrent tumour only.

Interestingly, a number of the previous cases of primary intracranial rhabdomyosarcoma have arisen from the meninges (e.g. 7, 10) and Smith et al.(10) have suggested that all primary intracranial rhabdomyosarcomas may arise from the meninges. Indeed, cranial skeletal muscle and meningothelial cells both arise from the neural crest. Furthermore, skeletal muscle cells have been identified in the meninges of patients without tumours (1, 5, 6, 9). However, the histogenesis of skeletal muscle cells in intracranial tumours remains controversial. In principle, the muscle cells may arise from the meningioma as a result of increasing anaplasia of the tumour. Alternatively, the tumour may arise from multipotent precursor cell capable of differentiating towards either cell type. Finally, the muscle cells may not be derived from the neoplastic cells at all. Instead they may have been driven to divide by factors released from the meningioma. In our patient the muscle cells appeared only in the recurrent tumour which would be most consistent with the former or latter explanations.

REFERENCES

  1. Ambler MW (1977) Striated Muscle Cells in the Leptomeninges in Cerebral Dysplasia Acta. Neuropath. 40:269-271
  2. Bradford R, Crockard HA, Isaacson PG (1985) Primary Rhabdoymosarcoma of the Central Nervous System: Case Report Neurosurgery 17:101-104
  3. Burger PC (1992) Comment Neurosurgery 30:785
  4. Ferracini R, Poggi S, Frank G, Azzolini U, Sabattini E, Spagnotti F, Cenacchi G, Pileri S (1992) Meningeal Sarcoma with Rhabdomyoblastic Differentiation: Case Report. Neurosurgery 30:782-785
  5. Hoffman SF, Rorke LB (1971) On Finding Striated Muscle in the Brain J. Neurol. Neurosurg. Psychiat. 34:761-764
  6. Johnson ES, Ludwin SK (1984) Rhabdoneuroglial Heterotopias of the Pontine Leptomeninges in Trisomy 13 Arch. Path. Lab. Med. 108:906-908
  7. Korinthenberg R, Edel G, Palm D, Müller K-M, Brandt M, Müller R-P (1984) Primary Rhabdomyosarcoma of the leptomeninx Clin. Neurol. Neurosurg. 86:301-305
  8. McLendon RE, Tien RD (1998) Tumors and tumor-like lesions of maldevelopmental origin. In: Russell and Rubinstein's Pathology of Tumours of the Nervous System, 6th Edition, Bigner DD, McLendon RE, Bruner JM (eds.) Volume 2, Chapter 15, pp. 295-370, Arnold: London, Sydney, Auckland
  9. Nakamura Y, Nakashima T, Komatsu Y, Hashimoto T, Hachisuka H (1984) Striated Muscle Cells in the Leptomeninges Arch. Pathol. Lab. Med. 108:561-563
  10. Smith MT, Armbrustmacher VW, Violett TW (1981) Diffuse Meningeal Rhabdomyosarcoma Cancer 47:2081-2086

Contributed by Thomas S Jacques, Alan Valentine, Robert Bradford, James E McLaughlin

International Society of Neuropathology