Brain Pathology Case of the Month - October 2000


FINAL DIAGNOSIS:

MULTIPLE, en plaque, LYMPHOPLASMACYTE-RICH MENINGIOMA

DISCUSSION:

Lymphoplasmacyte-rich meningioma was first described in 1971 by Banerjee and Blakwood (1). Horten et al. (2) reported five cases of such meningioma and observed that the proportion of neoplastic meningothelial cells is quite variable in relation to the plasma cell component. Plasma cells may predominate and only nests of epithelial cells remain, obscuring the underlying meningioma pattern. This variant differs from typical meningiomas, in which the infiltration of lymphocytes is usually discreet or may form perivascular cuffs. Stam et al. (3) affirmed that plasma cell infiltrates were not tumoral in origin, since these cells produced almost all classes of immunoglobulins. Some neuropathological studies have demonstrated that the inflammatory infiltrates may consist predominantly of T-lymphocytes (4,5).

Meningiomas constitute between 13 and 26% of primary intracranial tumors (6). Spinal meningiomas form only a small proportion, approximately 12%, of all meningiomas (7). Ten percent of meningiomas are multiple and occur most commonly with type-2 neurofibromatosis, although they can be found without this condition (6, 8). In the spinal canal, the thoracic region is more often involved than other levels. Meningiomas can be related or attached to a nerve root and rarely is the tumor entirely extradural (9). Another macroscopic variant is the meningioma en plaque, which is not greatly raised above the level of the dura mater, but is prone to invade the adjacent bone, with accompanying hyperostosis (7). Occasionally, they appear more diffuse and may grow en plaque over the convexity of the brain or form a collar-like mass around the spinal cord. They may compress adjacent structures and are more infiltrative of neural tissues. In our case, the tumor was restricted to the cervical portion of the spinal canal and infiltrated some nerve roots. Another important feature of our case was the growth pattern represented by the en plaque variant associated with multiple tumors, firmly adhered to the internal face of the dura.

Yamaki et al. (10) reported a spinal tumor which presented as an en plaque mass extending from the foramen magnum to C5 and encircled the spinal cord. They obtained positive staining for vimentin and EMA, indicating the meningothelial origin of the tumor. They also showed polyclonal characteristics of plasma cell infiltrates by immunohistochemical staining for kappa- and lambda-light chains.

No protein electrophoresis was performed in our case, but blood abnormalities are found in patients with lymphoplasmacyte-rich meningioma. Plasma cells are thought to secrete immunoglobulins across the blood-brain barrier and after complete removal of the tumor, blood abnormalities tend to disappear as well as reappear with relapse of the tumor (11).

Although the meningothelial component has been confirmed, whether the lesion is primarily neoplastic or simply granulomatous with a secondary meningeal reaction is an important question that remains unsolved (10). The exact differentiation between meningothelial hyperplasia and neoplasia, at the present, is probably impossible. The meningiomatous component in the lymphoplasmacyte-rich variant of meningioma may also be secondary to chronic inflammation, a fact that can not be ruled out.

REFERENCES

  1. Banerjee AK, Blackwood W (1971) A subfrontal tumor with the features of plasmocytoma and meningioma. Acta Neuropathol 18: 84-88
  2. Horten BC, Urich H, Stefoski D (1979) Meningiomas with a conspicuous plasma cell-lymphocytic componets. A report of five cases. Cancer 43: 258-264
  3. Stam FC, van Alphen HAM, Boorsma DM (1980) Meningioma with conspicuous plasma cell components. A histopathological and immunohistochemical study. Acta Neuropathol 49: 241-243
  4. Paine JT, Handa H, Yamasaki T, Yamashita J, Miyatake S (1986) Immunohistochemical analysis of infiltrating lymphocytes in central nervous system tumors. Neurosurg 18: 766-772
  5. Von Hanwehr RI, Hofman FM, Taylor CR, Apuzzo ML (1984) Mononuclear lymphoid populations infiltrating the microenvironment of primary CNS tumors. Characterization of cell subsets with monoclonal antibodies. J Neurosurg 60: 1138-1147
  6. Lantos PL, VandenBerg SR, Kleihues P (1996) Tumours of the nervous system. In: Greenfield's Neuropathology, Graham DI, Lantos PL (eds.), 6th Edition, Vol. 2.583-879, Arnold: London
  7. Russell DS, Rubinstein LJ (1989) Tumours of the meninges and related tissues. In: Pathology of Tumours of the Nervous System, 5th Edition, 449-532, Williams and Wilkins: Baltimore
  8. Ellison D, Love S, Chimelli L, Harding B, Lowe J, Roberts GW, Vinters HV (1998) Meningiomas. In: Neuropathology. A Reference Text of CNS Pathology, 43.1-43.14, Mosby: London
  9. Rubinstein LJ (1972) Tumors of the Central Nervous System, 169-190, Armed Forces Institute of Pathology: Washington
  10. Yamaki T, Ikeda T, Sakamoto Y, Ohtaki M, Hashi K (1997) Lymphoplasmacyte-rich meningioma with clinical resemblance to inflammatory pseudotumor. Report of two cases. J Neurosurg 86: 898-904
  11. Gi H, Nagao S, Yoshizumi H, Nishioka T, Uno J, Shingu T, Fujita Y (1990) Meningioma with hypergammaglobulinemia. Case report. J Neurosurg 73: 628-629

Contributed by José Eymard H. Pittella M.D., Cristiane C. da Costa M.D., Alexandre V. Giannetti M.D. and Francisco Otaviano L. Perpétuo M.D.


International Society of Neuropathology