Primary central nervous system T-cell lymphoma in aids patients : case report and literature review

A 43-year-old man presented to our hospital with headaches and right facial twitching for few days, associated with nausea and dizziness. His past medical history was significant for infection with hiv diagnosed 10 years earlier. Because of financial circumstances, the patient had stopped his haart 10 months earlier. On physical examination, the patient was alert and oriented. His vital signs were normal. He had a mild word-finding deficit, right facial droop, right pronator drift, and mild right arm hyperreflexia. The rest of the physical examination was normal. Laboratory work up showed a white blood cell count of 3400/mL, a CD4 count of 78/mL (normal: 493–1666/mL), an hiv viral load above 500,000/mL, positive Toxoplasma immunoglobulin G antibodies, negative serum cryptococcal antigen, and a nonreactive rapid plasma reagin test. Magnetic resonance imaging (mri) of the brain showed a large mass in the left frontoparietal region, with small non-enhancing lesions in the brain (Figure 1). A presumptive diagnosis of cerebral toxoplasmosis was made, for which the patient was treated with pyrimethamine, sulfadiazine, and leucovorin, with phenytoin for seizure prophylaxis. To avoid possible complications of anemia and immune reconstitution syndrome, haart was planned to be restarted 2 weeks later. The patient improved symptomatically and was discharged home. A follow-up brain mri 10 days later demonstrated no significant changes. One month later, the man came to our emergency department with a history of progressively increasing partial focal seizures that had started after he had stopped his medications 2 weeks earlier because of financial concerns. Brain mri showed a slight increase of the old left frontoparietal lesion ABSTRACT


INTRODUCTION
Pr imar y cent ral ner vous system ly mphomas (pcnsls) are an uncommon form of extranodal non-Hodgkin lymphoma, but they are becoming increasingly more frequent 1 .Currently, the incidence has increased to 4%-7% of newly diagnosed primary central nervous system (cns) tumours, and in the general population, the incidence rate is approximately 30 cases per million person-years 2 .More than 95% of pcnsls are B-cell lymphomas.T-Cell pcnsl is less well defined; its biologic behaviour and response to treatment have been difficult to evaluate because of its rarity.
In aids patients, the reported incidence of pcnsl is 1000 times that seen in the general population 3,4 .Most of the reported cases are B-cell pcnsl.A search of the medline database for pcnsl in aids patients found only 6 cases [5][6][7][8][9] .Here, we present another case of an aids patient with T-cell pcnsl, treated successfully with and small new enhancing lesions bilaterally.A computed tomography-guided brain biopsy showed atypical lymphocytes (Figure 2), positive staining for lymphocyte common antigen and the T-cell marker CD3 (Figure 3), and no staining for the Bcell marker CD20 (Figure 4).Immunoperoxidase staining for cytomegalovirus, Herpes simplex virus, and Toxoplasma was also negative.Giemsa, Gram, and acid-fast stains were also negative.
The patient refused chemotherapy, but underwent whole-brain external-beam radiation therapy and was started on haart.At the time of writing, he has been closely followed for 31 months; serial brain mri has shown stable disease, and the patient has been symptom-free.

DISCUSSION
A search of the medline database found only 6 other cases of T-cell pcnsl in aids patients [5][6][7][8][9] .Table i summarizes the clinical features of those cases and the present case.Median age of the patients is 38 years.The patients are predominantly male.
Primary central nervous system lymphoma can present with focal or non-focal signs and symptoms that have usually been present for fewer than 3 months.Patients with aids are more likely than other patients to present with altered mental status and seizures (50% vs. 35%) and less likely to show increased intracranial pressure (14% vs. 32%) 10 .Most of the patients in this review presented with focal neurologic symptoms.Patients with aids presenting with signs and symptoms suggestive of c ns disease should be evaluated radiologically.On computed tomography imaging, pcnsl usually appears as a well-defined focal lesion that can be isodense or hyperdense.The diagnostic yield is higher with mr i.
In immunocompetent patients, T-cell lymphomas present more frequently as infratentorial lesions.In the present review, most patients had lesions in the supratentorial region (Table i).
Measurement of Epstein-Barr viral dna in a sample of cerebrospinal fluid can aid in making the diagnosis, but stereotactic brain biopsy remains the definitive method 11 .Diagnosis of T-cell tumours can be difficult, and their incidence, despite being low, is possibly overestimated.Furthermore, B-cell neoplasms are frequently infiltrated by reactive T cells, complicating the interpretation of immunophenotyping.Staging is generally not indicated because pcnsl almost always remains confined to the cns.
Optimal treatment for pcnsl in a ids patients is not yet defined.Standard first-line treatment of radiation therapy and corticosteroids can achieve a complete response in 20%-50% of patients; median survival is 13.5 months, however 12 .The short survival reflects deaths from the opportunistic infections that are a result of the profound immunodeficiency that most patients with pcnsl already have 13 .Chemotherapy combined with radiation therapy may provide some benefit to patients with relatively high CD4 counts 13,14 .Among the patients in our review, treatment was reported for only 2, both of whom were treated with whole-brain radiation.
Some studies have suggested that survival is longer for patients with T-cell pcnsl 15 .Of the 7 patients in this review, 3 died soon after diagnosis, and the 2 that received treatment improved clinically; the fates of the other 2 were not reported (Table i).

CONCLUSIONS
In general, T-cell pcnsl is rare; it appears to be even more rare in immunocompromised patients.More reports of cases are needed to help improve diagnosis, treatment, and prognosis in this kind of lymphoma.

figure 1
figure1 Magnetic resonance imaging of the brain demonstrates an enhancing 2×3-cm mass involving the left frontoparietal region, and some small non-enhancing lesions in the brain bilaterally.

figure 3
figure3 Immunoperoxidase staining of the brain mass biopsy with the T-cell marker CD3 is extensive.