Epileptogenic Brain Metastasis Early Positive on 18FDG PET/CT Compared to MRI

Area of Science:

• Neurology
• Oncology
• Nuclear Medicine

Background:

• Metastatic small cell lung carcinoma (SCLC) can present with neurological symptoms.
• Standard Magnetic Resonance Imaging (MRI) may not always detect early metastatic lesions.
• Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) is a functional imaging technique.

Purpose of the Study:

• To report a case of SCLC with isolated tremor due to a metastatic lesion.
• To evaluate the utility of 18F-FDG PET/CT in detecting metastatic lesions missed by MRI.
• To highlight the role of functional imaging in diagnosing paraneoplastic neurological syndromes.

Main Methods:

• A patient with metastatic SCLC and isolated upper limb tremor underwent initial brain MRI.
• 18F-FDG PET/CT was performed, revealing hypermetabolism in the left precentral gyrus.
• A follow-up MRI with contrast enhancement confirmed cortical abnormalities correlating with PET findings.

Main Results:

• Initial brain MRI was normal, failing to identify the cause of the tremor.
• 18F-FDG PET/CT identified an isolated area of hypermetabolism in the left precentral gyrus.
• Follow-up MRI showed contrast enhancement in the corresponding cortical area, confirming metastatic involvement.

Conclusions:

• 18F-FDG PET/CT can detect symptomatic metastatic lesions in SCLC patients when MRI is normal.
• This case underscores the value of functional imaging in identifying subtle metastatic disease.
• PET/CT may aid in the early diagnosis and management of neurological complications in cancer patients.