"Slow and Steady" Infiltrates the Brain: An Autopsy Report of Lymphomatosis Cerebri.

Primary central nervous system lymphomas (PCNSL) usually present as single or multiple lesions with mass effect involving the cerebral hemispheres or basal ganglia. An extremely rare pattern of involvement termed "Lymphomatosis cerebri" (LC) presents as diffuse, non-enhancing infiltrative lesions without mass effect. We describe the clinical, radiological, and autopsy findings of one such rare example with a patient presenting with a short history of fever, memory loss, and progressive cognitive decline. Because of subtle yet rapidly progressive clinical symptoms and overlapping neuroimaging features, the diagnosis of LC is challenging with wide ranging differential diagnoses. The dilemma in diagnosing such lesions can lead to delay in diagnosis and institution of appropriate management. Thus, knowledge about its imaging and morphological features is very critical for correct categorization and to avoid potential misdiagnosis of this often-missed disease.