We reported a 61-year-old man presented with 10-month progressing left sciatic neuropathy and 10-day right facial neuropathy. Serum amphiphysin-IgG was positive. 18F-FDG PET/CT of the whole body showed no signs of malignancy. Treatment with plasma exchange and oral prednisone relieved the symptoms. Nine months later, right hemiparesis and seizure of right limbs developed. 18F-FDG and 18F-PBR06 (18 kDa translocator protein, TSPO) radioligand PET/MRI of the whole body revealed intense uptake in the intracranial lesions. Intracranial lymphoma was diagnosed by stereotactic needle brain biopsy. Mononeuropathies could be paraneoplastic syndromes. TSPO shows high uptake in intracranial lymphoma on 18F-PBR06 PET images.

BACKGROUND: Cranial nerve involvement is not commonly encountered in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP); this is especially true for involvement of the hypoglossal nerve. Neither Beevor\'s sign nor its inverted form has previously been described in CIDP.
METHODS: A 28-year-old man presented with distal-predominant limb weakness and numbness at the age of 18. A diagnosis of CIDP was made, which was confirmed by electrodiagnostic evidence of demyelination. He responded well to intravenous immunoglobulin and glucocorticoid treatment and achieved remission for 5 years. However, the same symptoms relapsed at the age of 28 and lasted for 10 months. On examination, in addition to limb sensory impairment and muscle weakness, mild bilateral facial paresis, tongue atrophy and fasciculations, and inverted Beevor\'s sign were also observed. A brief literature review of cranial nerve involvements in CIDP and Beevor\'s sign or its inverted form were also performed.
CONCLUSIONS: Cranial nerves may be affected in patients with CIDP. Facial palsy is most frequently present, while hypoglossal nerve involvement is rare. Inverted Beevor\'s sign can appear in CIDP patients.