[Neuronal intranuclear inclusion disease diagnosed by brain biopsy: a clinicopathological analysis of seven cases]

Objective: To investigate the clinical, imaging and neuropathological characteristics of neuronal intranuclear inclusion disease (NIID) with symptoms of the central nervous system, and to improve the diagnosis and treatments of NIID. Methods: The clinical data of 7 patients with NIID diagnosed by brain biopsy in Xuanwu Hospital, Capital Medical University, Beijing, China from February 2009 to December 2024 were collected. The characteristics of clinical manifestations, imaging, and histology on brain biopsy were retrospectively analyzed. Results: Among the 7 patients, 5 were male and 2 were female. Their ages ranged from 44 to 70 years, median 56 (52, 65) years. Patients were classified into three types of tumor, stroke and encephalitis according to the onset symptoms, imaging manifestations and pathological changes. The chief complaint of the 5 patients was headache, while 4 patients had paroxysmal convulsions, 3 had speech disorders, 2 had abnormal mental behaviors, 2 had memory decline, and 1 had fever accompanied by consciousness disorders. Diffusion-weighted magnetic resonance imaging of the head showed the "ribbon sign" at the junction of the cortex and medulla in 2 cases. Most of the patients had white matter lesions, gyrus swelling and cerebral atrophy. Occasionally gyrus-like enhancement was observed. Brain biopsy reveals the histological changes that matched those on images and initial symptoms. There were proliferation of oligodendrocytes and astrocytes in the white matter, leukoaraiosis and edema, cortical disintegration and lamellar necrosis, as well as infiltration of lymphocytes and microglia, etc. However, the characteristic changes were eosinophilic hyaline inclusions in the nuclei of neurons and astrocytes. Immunohistochemical staining of p62 and ubiquitin showed homogeneous staining in round or ring-shaped nuclei. Conclusions: The clinical manifestations of NIID are highly variable, and a correct diagnosis of NIID requires careful integration of clinical, imaging and histopathologic data. For patients with a high suspicion of NIID, immunohistochemical staining of p62 and ubiquitin is diagnostically valuable.