Primary central nervous system lymphoma: A mirror type presentation in an immunocompetent patient.

Background: Primary central nervous system (CNS) lymphoma is a very rare extranodal non-Hodgkin lymphoma. The bilateral pattern, as we call it "mirror type", has been identified in other CNS lesions such as gliomas, metastases, and demyelinating lesions, so the differential diagnosis includes imaging studies such as magnetic resonance imaging contrasted with spectroscopy, ruling out immunodeficiency or metastatic disease. Case Description: A 65-year-old female presented progressing headache, loss of memory and language alterations, as well as sensory alterations. Neuroimaging showed the presence of two equidistant periventricular lesions at the level of both ventricular atria, a spectroscopy study suggestive of malignancy. Serological studies showed no evidence of immunodeficiency or the presence of positive tumor markers; however, a biopsy was performed, which revealed a histopathological result of primary lymphoma of the CNS. Conclusion: In neuro-oncology, primary CNS tumors with multiple lesions are rare, even more, the "mirror type" lesions. Lymphomas are lesions that can present in different ways on imaging and clinical presentation. These tumors that present a vector effect due to their size, perilesional edema, or that lead to loss of neurological function are highly discussed in diagnostic and surgical treatment. Due to their prognosis, action on diagnosis and treatment must be taken as quickly as hospital resources allow.