LAUSR

A 71-year-old man presented with diplopia and periorbital pain. The clinical examination showed left-sided incomplete external oculomotor nerve palsy. The remainder of the neurological and ophthalmological examination was unremarkable except for slight polyneuropathy. He was on medication treating diabetes and arterial hypertension. Two months earlier a diffuse large cell B-lymphoma was diagnosed based on histology of a pleura biopsy. He was treated with three cycles of chemotherapy according to the R-CHOP scheme (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Cerebral magnetic resonance imaging (MRI) demonstrated no abnormal finding (Fig. 1a). The lumbar puncture revealed pleocytosis (600 cells pro ll; normal \4), elevated protein (658 mg/dl; normal\450), elevated lactate (6.7 mmol/l; normal\2.2) and diminished glucose (35 mg/dl compared to serum 159 mg/dl). Antibody specificity indices of Borrelia burgdorferi, varicella virus, and herpes virus were within normal limits. By PCR no DNA of varicella zoster virus and herpes virus were detected. Cytopathological examination of the CSF showed a marked increase of the number of cells. The cells were relatively monomorphic and revealed blastic features compatible with diagnosis of meningeosis lymphomatosa (Fig. 1b, c). A high dose systemic chemotherapy was initiated. Isolated oculomotor nerve palsy is not infrequent and needs a broad differential diagnostic approach [1]. Such palsy due to lymphoma, however, is quite rare and since the first description of it in 1979 only a few reports had been published [2–5]. Beside lymphomatous infiltration, space-occupying effects and paraneoplastic mechanisms are discussed [3, 5]. Our case is interesting for two reasons. First, gadolinium-enhanced MRI showed no abnormality and no enhancement. In the hitherto reported cases on oculomotor nerve palsy in association with histologically proven diffuse large cell B-lymphoma typically an enhancement and enlargement of the oculomotor nerve or an enhancement of the cavernous sinus and its surrounded structures were observed [4]. It is therefore important to take into consideration that a normal MRI in itself does not exclude a lymphomatous process in a patient with oculomotor nerve palsy. Second, the CSF pattern with pleocytosis, elevation of protein and lactate encountered in this patient can mimic an infectious disease, such as borreliosis, tuberculosis, or even a viral infection, which were excluded by specific tests. The cytopathological examination ultimately showed the way for the diagnosis by demonstrating monomorphic cells with blastic features. To conclude, unilateral third nerve palsy in association with meningeosis of diffuse large cell B-lymphoma is a rare clinical condition. Clinicians should be aware of such rare entities and beside neuroimaging lumbar puncture should strongly be considered.