LAUSR

A 54-year-old woman started to experience sharp bilateral frontotemporal headaches 2 months prior to our consultation. Headaches recovered spontaneously. She had been experiencing the same headaches during the past 15 years and had no other diseases in history. The initial magnetic resonance imaging (MRI) showed T2 and fluid-attenuated inversion recovery (FLAIR) hyperintensities located in the left hemisphere (Fig. 1). The finding was supposed to be a consequence of vasculitis or cerebral lymphoma. At the time of admission, the neurological examination was normal, patient complained on mild binocular blurred vision. The repeated MRI with spectroscopy showed no progression of the lesion, slightly lower N-acetyl aspartate (NAA) and moderate increase of creatine and choline. MRI tractography showed thinner fibres which were discretely apart. Progressive multifocal leukoencephalopathy (PML) was suspected. Testing for infectious diseases including polymerase chain reaction (PCR) for John Cunningham (JC) virus was negative. Laboratory findings, including an extended immunological panel and very long-chain fatty acid (VLCFA) levels and cerebrospinal fluid (CSF) analysis, were normal. The visual evoked potential test indicated a mild lesion of left optic association fibres. Due to lack of information, we decided to perform a stereotactic biopsy. The pathohistological analysis of samples revealed perivascular infiltration of small lymphocytes which were partially positive for CD3, CD5 and CD20 and negative for CD10, CD30 and cyclin D1 on immunohistochemistry. The pathologist suspected low-grade B non-Hodgkin lymphoma. The further investigation of the clonality of lymphocytes detected a reactive lowgrade (non-clonal) infiltration with all cells expressing a polyclonal pattern of rearrangement of B-cell immunoglobulin genes. The finding excluded a haematological disease. The repeated MRI scans at 6 and 13-month follow-up showed no change of the lesion. Regarding neurological complaints, only mild binocular blurred vision persisted. White matter diseases do not come with a standard differential diagnosis and a standard battery of tests to be performed. The choice of diagnostic test is highly influenced by observed MRI pattern [1]. It was estimated that 30–40% of patients of all ages with white matter abnormalities on MRI remain without a specific diagnosis [1]. A unilateral white matter lesion without clear neurological complaints had previously been reported in one adult patient, in whom authors suggested unilateral Krabbe disease [2]. The diagnosis was further refuted by Van der Knaap [3]. In our patient, we have excluded diagnoses suggested for detected MRI pattern. Findings of diagnostic work-up performed in our patient resulted in failure to achieve a definite diagnosis. Genetic cause is unlikely, given the clinical presentation and the fact that most genetic white matter disorders present with confluent and bilateral, essentially symmetric, white matter abnormalities [1]. In this case, the nature of MRI abnormalities and mild non-progressive complaints present an obstacle for further diagnostic work-up. Hence, a decision for clinical and MRI follow-up was made. In conclusion, we assume our patient enters a previously estimated percentage of patients with white matter abnormalities who remain without a specific diagnosis. * Ivana Markovic [email protected]