Primary central nervous system immunocytoma: MRI and spectroscopy

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Neuroradiology (2000) 42: 738±741 Ó Springer-Verlag 2000

E. Braks H. Urbach H. Pels F. Träber W. Block H. H. Schild

Received: 21 January 2000 Accepted: 15 February 2000

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E. Braks ( ) × H. Urbach × F. Träber × W. Block × H. H. Schild Department of Radiology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany Tel.: + 49-2 28-2 87-63 89 Fax: + 49-2 28-2 87-43 21 H. Pels Department of Neurology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany

D IA G N O S T I C NE UR OR A DI O LO G Y

Primary central nervous system immunocytoma: MRI and spectroscopy

Abstract We report on a young woman with a primary cerebral immunocytoma. Most primary cerebral nervous system lymphomas (PCNSL) are highly malignant undifferentiated B-cell tumours, there are few data on the clinical course, MRI and spectroscopy findings of this rare PCNSL subtype. MRI revealed a radially enhancing tumour with mild perifocal oedema. MR spectroscopy indicated low cell turnover. Slow clinical progression, no significant changes with treatment, and imaging findings were

Introduction In the past 20 years, the incidence of primary central nervous system lymphoma (PCNSL) has been increasing in both immunocompetent and -compromised patients. To date, PCNSL represents 1±3 % of brain neoplasms [1±3]. PCNSL are highly cellular tumours, typically around the ventricular system; however, they can occur as uni- or multifocal lesions in any location [4±9]. Atypical PCNSL often present a diagnostic challenge. We report a young woman with a primary CNS immunocytoma, a rare immunohistochemical subtype of PCNSL [10]. The tumour showed MRI and spectroscopy (MRS) features most likely due to its histologically and clinically proven low grade of malignancy.

Case report A 42-year-old woman was studied with MRI because of headaches and vertigo. T 1-weighted spin-echo images demonstrated a low-signal lesion with mild mass effect in the right centrum

consistent with a low-grade malignant tumour. Key words Lymphoma × Central nervous system × Immunocytoma, cerebral × Magnetic resonance imaging × Magnetic resonance spectroscopy

semiovale. Faint contrast enhancement was shown, radiating from the right lateral ventricle (Fig. 1). On T 2-weighted fast SE images, the lesion gave higher signal than cortex, and there was oedema in the surrounding white matter (Fig. 2). Two years later the patient developed aphasia and complex partial seizures followed by a right hemiparesis with a strength of 4/5. MRI now showed a slightly larger lesion with more prominent radial enhancement. Digital subtraction angiography revealed a fine radial net of irregular vessels in the late venous phase draining into the thalamostriate vein (Fig. 3). H1-MRS showed an elevated lactate doublet, a slightly increased choline (Cho) peak, and reduced signals from total creatinine ( (P)Cr) and N-acetylaspartate (NAA) (Fig. 4 a). During the following year, the number and intensity of the seizures increased and they finally became medically intractable. MRI showed a further slight increase in size of the lesion. On MRS, Cho and (P)Cr levels remained stable, while a minor increase in lactate and decrease in NAA were seen (Fig. 4 b). As the frequency of the seizures increased dramatically, glucocorticoid therapy was initiated. Two weeks later stereotactic biopsy of the frontal lobe was performed. Immunohistochemical analysis revealed a low-grade malignant lymphoplasmacytic lymphoma of B-cell origin, a so-called immunocytoma, with a small growthfraction of 5 %. Small vessels surrounded by clusters of lymphoid cells were found. As seizures could not be controlled, immediate

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Fig. 1 Axial T 1-weighted MRI shows a low-signal lesion with radial contrast enhancement Fig. 2 On a T 2-weighted fast spin-echo image the lesion gives high signal Fig. 3 Digital subtraction angiography (late venous phase) shows a fine radial net of irregular vessels draining into the thalamostriate vein treatment with combined systemic and intraventricular chemotherapy was started. The seizures stopped with this regime and anticonvulsant therapy. Apart from a slight fall of the lactate doublet and decrease in tumour-associated oedema, MRS and MRI findings were unchanged after 6 months of treatment (Fig. 5).

Fig. 4 a H1 MRS shows an elevated lactate doublet, a slightly increased choline peak (Cho), and reduced signals from total creatinine ( (P)Cr) and N-acetylaspartate (NAA). b A year later, Cho and (P)Cr levels remain stable, but there has been a minor increase in lactate and decrease in NAA

3 Discussion PCNSL have histopathological and immunohistochemical characteristics similar to systemic extranodal nonHodgkin's lymphomas; they are now categorised according to the REAL-classification [11]. PCNSL are neoplastic transformations of lymphoid cells in different stages of differentiation from stem cell to plasma-, centro- and lymphocytes. Most tumours are highly malignant, undifferentiated large B-cell lymphomas (80 %), named according to the largest fraction of lymphoid subtypes [4, 12]. The present lymphoplasmacytic B-cell lymphoma, also called immunocytoma [13], is a rare subtype originating from the more differentiated plasmacytic precursor cells (Table 1). Most PCNSL share the imaging features of other densely packed tumours, bearing cells with a high nucleus-to-cytoplasm ratio [6, 8]. The tumours are therefore isodense with or denser than brain parenchyma on

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Fig. 5 Coronal T 1-weighted MRI shows no significant change in the radially-enhancing immunocytoma

Table 1 Incidence of immunocytomas (REAL classification) [11] Reference

All primary central nervous system lymphomas

Immunocytomas (%)

[12] [4] [8] [13] [15] [10] Total

152 41 15 29 68 83 776

16 (11) 4 (10) 2 (13) 1 (4) 19 (28) 13 (16) 55 (7)

CT and almost isointense with cortex on T 1- and T 2weighted MRI. PCNSL usually enhance homogeneously, which is explained by their growth along vessel walls, within the perivascular spaces, whence they infiltrate the brain parenchyma. Contrast enhancement typically disappears under the lymphocytotoxic effect of

steroids. Although this behaviour is highly suggestive of PCNSL, no steroids should be given before brain biopsy, to avoid false-negative results. A well known exception to the homogeneous contrast enhancement is the irregular, peripheral enhancement of centrally necrotic PCNSL in patients with AIDS. Radial enhancement, as in our case has been described in a case in which tumour growth was histologically limited to the perivascular spaces [16]. Few PCNSL, all highly malignant B-cell lymphoma, have been examined by MRS [9, 17]. The tumours behaved like glioblastomas, with metabolite changes indicating a high cell-membrane turnover (high Cho peak) and neuronal damage (NAA decrease and lactate doublet). The high cell-membrane turnover is in accordance with rapid growth of the tumour, untreated patients usually surviving only 3±5 months [5]. On the other side, high mitotic activity results in an impressive response to steroids, irradiation and chemotherapy, prolonging mean survival for up to 4 years [2, 18±20]. In the present case of a more highly differentiated PCNSL, a lesser degree of metabolite changes on MRS and no significant change on follow-up were similar to the findings in low-grade gliomas. The low mitotic activity is probably responsible for the slow clinical progression over 2 years without treatment and the relative resistance to treatment. We must concede that the histological diagnosis of a low-grade malignant lymphoma in this case is dibatable because biopsy was preceded by steroid therapy. However, the slow clinical progression, no significant change with treatment, and MRI and MRS findings were indicative for a low degree of malignancy.

References 1. Hochberg FH, Miller DC (1988) Primary central nervous system lymphoma. J Neurosurg 68: 835±853 2. DeAngelis LM, Yahalom J, Thaler HAT, Kher U (1992) Combined modality therapy for primary CNS lymphoma. J Clin Oncol 10: 635±643 3. Eby NL, Grufferman S, Flannelly CM, Schold SC Jr, Vogel FS, Burger PC (1988) Increased incidence of primary brain lymphoma in the US. Cancer 62: 2561±2465 4. Bergmann M, Kuchelmeister K, Winkelmüller W, Braun W, Behrens E, von Wild K (1993) Primary intracerebral non-Hodgkin-lymphoma ± a clinico-pathological study. Zentralbl Neurochir 54: 110±118 5. Fine HA, Mayer RJ (1993) Primary central nervous system lymphoma. Ann Intern Med 19: 1093±1104

6. Johnson BJ, Fram EK, Johnson PC, Jacobowitz R (1997) The variable MR appearance of primary lymphoma of the central nervous system: comparison with histopathologic features. AJNR 18: 563±572 7. Vandermarcq C, Drapeau C, Ferrie JC (1997) Aspects par imagerie des lymphomes cØrØbraux primitifs. Neurochirurgie 43: 363±368 8. Stock KW, Müller T, Radü EW, Steinbrich W (1993) Intracranial lymphoma ± radiological findings in 40 patients. Fortschr Röntgenstr 158: 565±568 9. Chang L, Miller BL, McBride D, Cornford M, Oropilla G, Buchthal St, Chiang F, Aronow H, Ernst T (1995) Brain lesions in patients with AIDS: H1 MR spectroscopy. Radiology 197: 525±531

10. Boghdan U, Bogdahn S, Mertens HG, Dommasch D, Wodarz R, Wunsch PH, Kuhl P, Richter E (1986) Primary nonHodgkin's lymphomas of the CNS. Acta Neurol Scand 73: 602±614 11. Harris NL, Jaffe ES, Stein H, Banks PM, Chan JK, Cleary ML, Delsol G, De Wolf Peeters C, Falini B, Gatter KC (1994) A revised European-American classification of lymphoid neoplasms: a proposal from the International Lymphoma study Group. Blond 84: 1361±1392 12. Menet E, Goujon JM, Levillain P, Babin P (1997) Anatomie pathologique des lymphomes cØrØbraux primitifs. Neurochirurgie 43: 357±360

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13. Kanavaros P, Mikol J, Nemeth J, Galian A, Dupont B, Thibaut JB, Thurel C (1990) Stereotactic biopsy diagnosis of primary non-Hodgkin's lymphoma of the central nervous system. A histological and immunohistolochemical study. Pathol Res Pract 186: 459±466 14. Lennert K, Feller AC (1990) Histopathologie der Non-Hodgkin-Lymphome (nach der aktualisierten Kiel-Klassifikation). Springer-Verlag, Berlin Heidelberg New York 15. Jellinger K, Radaskiewicz TH, Slowik F (1975) Primary malignant lymphomas of the central nervous system in man. Acta Neuropathol Suppl (Berl) 6: 95±102

16. Atlas SW, Lavi E (1986) Intraaxial brain tumors. In: Atlas SW (ed) Magnetic resonance imaging of the brain and spine. Lippincott-Raven, Philadelphia New York, p 305 17. Bizzi A, Movsas B, Tedeschi G, Phillips CL, Okunieff P, Alger JR, Di Chiro G (1995) Response of non-Hodgkin lymphoma to radiation therapy: early and long-term assessment with H-1 MR spectroscopic imaging. Radiology 194: 271±276 18. Abrey LE, De Angelis LM, Yahalom J (1998) Long-term survival in primary CNS lymphoma. J Clin Oncol 16: 859±863

19. Glass J, Shustik C, Hochberg FH, Cher L, Gruber ML (1996) Therapy of primary central nervous system lymphoma with preirradiation methotrexate, cyclophosphamide, doxorubicin, vincristine and dexamethasone (MCHOD). J Neuro-oncol 30: 257±265 20. Schlegel U, Pels H, Glasmacher A, Kleinschmidt R, Bode U (1998) Combined high-dosage polychemotherapy as efficient single therapy of primary cerebral lymphoma. Akt Neurol 25: 297±303

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