Primary central nervous system lymphoma presenting as a unilateral internal auditory canal lesion: a case report

• Published in: Rinsho Shinkeigaku Vol. 64; no. 5; pp. 349 - 355
• Main Authors: Tohge, Rie, Iwase, Masaaki, Kondo, Takayuki
• Format: Journal Article
• Language: Japanese
• Published: Japan Societas Neurologica Japonica 24.05.2024
• Subjects: Central Nervous System Neoplasms - diagnosis; Central Nervous System Neoplasms - diagnostic imaging; Diagnosis, Differential; Ear, Inner - diagnostic imaging; Ear, Inner - pathology; Gallium Radioisotopes; Hearing Loss, Sudden - diagnosis; Hearing Loss, Sudden - etiology; Humans; Lymphoma - diagnosis; Magnetic Resonance Imaging; Male; malignant lymphoma; Middle Aged; Neuroma, Acoustic - diagnosis; Neuroma, Acoustic - diagnostic imaging; Receptors, Interleukin-2 - blood; Single Photon Emission Computed Tomography Computed Tomography; sudden deafness; tumors in the internal auditory canal; vestibular schwannoma; tumors in the internal auditory canal; sudden deafness; malignant lymphoma; vestibular schwannoma
• ISSN: 0009-918X; 1882-0654
• DOI: 10.5692/clinicalneurol.cn-001939

A 61-year-old man with right hearing loss and staggering for seven months was diagnosed with sudden deafness although previous evaluation with MRI indicated minor abnormal findings. During follow-up, he developed hypogeusia, right facial nerve palsy, pain in right mandible, right-sided temporal pain, and cerebellar ataxia. Cerebrospinal fluid examination at admission revealed reduced glucose concentration and elevated soluble interleukin-2 receptor (sIL-2R) level, whereas serum sIL-2R level was within the normal range. Brain MRI showed a swollen contrast-enhanced lesion extending from the right internal auditory canal to the middle cerebellar peduncle. Gallium-67 (67Ga) single-photon emission-computed tomography-computed tomography (SPECT-CT) revealed abnormal accumulation at the lesion site. Pathologic analysis of the tumor after resection led to the diagnosis of primary central nervous system lymphoma. In the present case, the MRI and 67Ga SPECT-CT characteristics were distinct from those of vestibular schwannoma. In addition, elevation of sIL-2R in the cerebrospinal fluid but not in serum was useful for differential diagnosis.