Acute Encephalitis in an Adult with Diffuse Large B-Cell Lymphoma with Secondary Involvement of the Central Nervous System: Infectious or Non-Infectious Etiology?

Abstract

Both infectious and non-infectious etiologies of acute encephalitis have been described, as well as their specific presentations, diagnostic tests, and therapies. Classic findings of acute encephalitis include altered mental status, fever, and new lesions on neuroimaging or electroencephalogram (EEG). We report an interesting case of a 61-year-old male with a history of diffuse large B-cell lymphoma with secondary involvement of the central nervous system (SCNS-DLBCL). He presented with acute encephalitis: altered mental status, fever, leukocytosis, neuropsychiatric symptoms, multiple unchanged brain lesions on computed tomography scan of the head, and EEG showed mild to moderate diffuse slowing with low-moderate polymorphic delta and theta activity. With such a wide range of symptoms, the differential diagnosis included paraneoplastic and autoimmune encephalitis. Infectious and autoimmune/paraneoplastic encephalitis in patients with SCNS-DLBCL are not well documented in the literature, hence diagnosis and therapy becomes challenging. This case report describes the patient's unique presentation of acute encephalitis.

Keywords: autoimmune encephalitis; diffuse large B-cell lymphoma; infectious encephalitis; neuropsychiatric presentation of encephalitis; paraneoplastic encephalitis.

Figure 1

Computed tomography (CT) head of a 61-year-old male with SCNS-DLBCL presenting with acute encephalitis. (a) CT Head shows a small area of inferolateral left temporal density, which correlates with the blood products that were seen in patient’s previous magnetic resonance imaging (MRI) associated with the temporal lobe lesion. There is associated white matter low density, which is similar to the non-enhancing signal on previous MRI; (b) CT Head shows a small area of medial left parietal occipital low density corresponds to the lesion and old blood seen on the MRI. It also shows a very small area of medial right parietal occipital low density corresponds to signal seen on the MRI.

Figure 2

Electroencephalogram (EEG) of a 61-year-old male with SCNS-DLBCL presenting with acute encephalitis. Consistent with an abnormal EEG reading due to mild-moderate diffuse slowing. This specific frame shows excess low to moderate voltage (15 to 40 uV) polymorphic delta and theta activity. Interpretation of this EEG suggests mild to moderate diffuse cerebral dysfunction. Technical information: Electrodes were placed according to the 10–20 International Electrode System. Digital EEG was recorded using the Natus Digital EEG System and EEG was reformatted into multiple montages as needed.