Primary central nervous system lymphomas (PCNSL) are rare neoplasms, the most common subtype is diffuse large B-cell lymphoma. The treatment of PCNSL remains a challenge.

To present a clinical case of PCNSL in which surgical resection was performed, but early disease relapse occurred.

A 64-year-old woman, medical history of rheumatoid arthritis, presented to the HSPE emergency department due to sudden severe headache in the left hemisphere, without focal neurological deficits. Computed tomography (CT) of the brain showed oval intraparenchymal lesions with hemorrhagic component, located in the left temporal lobe, with expansive effect, and in parietal periventricular region on the right side. Complementary magnetic resonance imaging (MRI) of the brain revealed an expansive lesion near the temporal horn of the left lateral ventricle, measuring approximately 1.9 cm, and another lesion in the medial posterior horn of the right lateral ventricle, measuring 1.6 cm. Biopsy of one of the lesions was performed, but 20 days after the procedure, the patient developed motor deficit on the right side and global aphasia, and thus, resection of the left temporal lesion was performed. Histopathological and immunohistochemistry were consistent with DLBCL (CD3 +, CD 20 +, Ki-67 55%, TP53 +). Contrast-enhanced CT scans did not show systemic lymphadenopathy. One month after the resection, there was tumor relapse with the presence of a mass measuring 6 x 3 x 2.8 cm on MRI, located near the surgical cavity margins. Therefore, treatment with Methotrexate (MTX) 3 g/m2 associated with Rituximab 375 mg/m2 and dexamethasone was chosen. After 13 days of chemotherapy, the patient died.

PCNSL is rare and generally presents aggressive behavior, its involvement is confined to the brain, spinal cord, and/or cerebrospinal fluid; 90% are DLBCL. They are often associated with EBV or HIV infection and also affect transplant patients or those with autoimmune diseases, as in the reported case. They usually do not present B symptoms as manifestations, but rather neurological symptoms such as speech and/or motor disorders, mental confusion, seizures, and change on consciousness level. The diagnosis is made through biopsy of the CNS lesion, or evaluation of the CSF. Treatment for PCNSL generally consists of systemic chemotherapy and high-dose MTX is essential in therapy. Despite being a subtype of lymphoma that responds well to treatment, it has high relapse rates. The use of high-dose MTX for elderly patients is associated with greater toxicity. Surgical approach is usually not performed and currently has a diagnostic role, however, there are few studies in literature demonstrating increased survival when surgical resection of the mass is performed.

The treatment of patients with PCNSL remains a challenge due to the difficulty in defining an effective treatment with lower toxicity and the severity of sometimes irreversible sequelae. The discussion about surgical approach is still limited to a few studies, and the benefit in terms of survival has not been fully clarified.