Measurement of cerebrospinal fluid ACE level in aseptic meningitis: diagnostic?

Neurosarcoidosis Presented as an Isolated Brain Lesion

Sarcoidosis is a multisystemic, noncaseating granulomatous disease of unknown etiology. Neurosarcoidosis (NS) is the involvement of the central nervous system (CNS) in sarcoidosis, and it occurs in approximately 5%-10% of cases. NS can present with a variety of clinical features, making diagnosis challenging. A comprehensive diagnostic approach is required to obtain a definitive diagnosis. In this case we present a 13-year-old boy with diabetes mellitus presented with acute right-sided weakness, paresthesia, headaches, and episodes of loss of consciousness, followed by confusion and aggressive behavior. Neurological examination revealed right-sided motor and sensory deficits, as well as abnormal reflexes. Cranial imaging revealed a solitary lesion in the left centrum semi-ovale. Cerebrospinal fluid (CSF) analysis showed lymphoblastic leukocytosis, increased CSF angiotensin-converting enzyme (ACE), and a high IgG index. Extensive laboratory and imaging studies ruled out other potential etiologies. This case presented with a unique set of clinical features, including a mass lesion effect and seizures, which are uncommon in isolated NS. The patient responded well to high-dose corticosteroid therapy, with resolution of his symptoms. Levetiracetam was used to effectively manage his seizures.

Histone-mutant glioma presenting as diffuse leptomeningeal disease

Glioblastoma multiforme is the most common malignant primary brain tumor in adults. Histone H3 mutations have been identified in pediatric and adult gliomas, with H3K27M mutations typically associated with a posterior fossa midline tumor location and poor prognosis. Leptomeningeal disease is a known complication of histone-mutant glioma, but uncommon at the time of initial diagnosis. We describe a case of glioblastoma with H3K27M mutation that initially presented with progressive vision loss due to diffuse leptomeningeal disease in the absence of a mass lesion other than a small cerebellar area of enhancement and with cerebrospinal fluid cytology negative for malignant cells on two occasions, highlighting the importance of including primary CNS malignancies in the differential of diffuse radiographic leptomeningeal enhancement.

Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor in adults. Histones are molecules around which DNA winds. GBM and other gliomas sometimes have genetic alterations called mutations in histone genes. Of these, a specific alteration in histone 3 called H3K27M has been described in a variety of primary brain tumors. In adult gliomas, the H3K27M mutation is typically associated with tumors located within the brainstem or other structures in the midline of the central nervous system and a poor prognosis. Although previously reported, involvement of the leptomeninges (the thin membranes covering the brain and spinal cord) is uncommon at the time of initial diagnosis of gliomas harboring H3K27M mutations. We describe a case of GBM that initially presented with vision loss due to diffuse leptomeningeal involvement. Imaging and laboratory studies, including two cerebrospinal fluid analyses by lumbar puncture, did not establish a diagnosis. Brain biopsy confirmed the presence of a tumor, and genetic testing performed on the tumor tissue identified the histone mutation. This case highlights the importance of including primary central nervous system malignancies as a possible diagnosis when there is diffuse radiographic leptomeningeal enhancement.

Sarcoidosis Presenting as Cranial Multinevritis

A 29-year-old woman presented to the emergency department with red eyes and hypoacusia since the previous weeks associated with a sudden right facial palsy. Ophthalmologic examination revealed bilateral uveitis and lumbar puncture was compatible with aseptic meningitis. Thoracic computed tomography scan showed pulmonary nodules and mediastinal and hilar lymphadenopathy. Bronchoalveolar lavage revealed a CD4/CD8 ratio of 8, and lymph node biopsy confirmed non-caseating granulomas. The diagnosis of sarcoidosis with ocular, pulmonary, and neurologic involvement was made. Due to sarcoidosis severity at presentation, the patient was started on systemic steroids and methotrexate with improvement. Sarcoidosis involvement of the central nervous system is a rare condition (5-10%) but can be the first manifestation of the disease. Its presentation can be heterogeneous; therefore, symptoms are frequently devalued by patients and physicians, leading to a late diagnosis and permanent damage. Clinicians’ awareness is crucial to early diagnosis and treatment.